Invalid typecast error at design time

[gurkc006]

Hi Dave,
I'm using the InstrumentLab 6.0 (and PlotLab 6.0) in Delphi XE2 for evaluating. I Installed the setup.exe and everything seems to be fine. I can use the components as desired and they seem to work.
But I have a strange problem at design time, when I use the Delphi property inspector for all Mitov components. For some deeper nested properties I get an Invalid type cast error box, which appears on and on, until I manage somehow to close this property "branch" again. It seems to be always the case, when there is the variable "value" and/or "proportional" in the branch.
I already tried to reinstall the Instrument-/PlotLab, but nothing changed.
This are the details from the error dialog:

[50181ACF]{rtl160.bpl } System.Rtti.TValue.FromOrdinal (Line 2229, "System.Rtti.pas" + 3) + $12
[1108A819]{Mitov.Runtime.D16.bpl} RTRtti.TRTSingleProperty.GetDefault$qqrv + $1ED
[500431C7]{rtl160.bpl } System.TInterfacedObject.QueryInterface (Line 30135, "System.pas" + 1) + $8
[117C5E6E]{Mitov.Delphi.Design.D16.bpl} Mitov.Design.Design.TSinglePropertyEditor.GetDefaultValue$qqrv (Line 2879, "Mitov.Design.pas" + 1) + $1B
[117CE5F0]{Mitov.Delphi.Design.D16.bpl} Mitov.Design.Design.TFloatPropertyEditor.GetDefaultValue$qqrv (Line 5376, "Mitov.Design.pas" + 13) + $6
[117CE64E]{Mitov.Delphi.Design.D16.bpl} Mitov.Design.Design.TFloatPropertyEditor.GetIsDefault$qqrv (Line 5381, "Mitov.Design.pas" + 1) + $1F
[500431C7]{rtl160.bpl } System.TInterfacedObject.QueryInterface (Line 30135, "System.pas" + 1) + $8
[50076052]{rtl160.bpl } System.SysUtils.Supports (Line 22344, "System.SysUtils.pas" + 1) + $9
[117AABFD]{Mitov.Delphi.Design.D16.bpl} Mitov.Delphi.PropertyEditors.Delphi.Propertyeditors.TFloatPropertyEditorProxy.Ge​tIsDefault$qqrv (Line 2141, "Mitov.Delphi.PropertyEditors.pas" + 1) + $8
[21119096]{vclide160.bpl} PropBox.TCustomPropListBox.DrawPropItem (Line 926, "PropBox.pas" + 172) + $5
[5030C98B]{vcl160.bpl } Vcl.Graphics.TResourceManager.AssignResource (Line 1958, "Vcl.Graphics.pas" + 17) + $D
[211197B6]{vclide160.bpl} PropBox.TCustomPropListBox.CNDrawItem (Line 1134, "PropBox.pas" + 12) + $2E
[50332995]{vcl160.bpl } Vcl.Controls.TControl.WndProc (Line 7204, "Vcl.Controls.pas" + 91) + $6
[5033695D]{vcl160.bpl } Vcl.Controls.TWinControl.MainWndProc (Line 9692, "Vcl.Controls.pas" + 6) + $0
[500B6890]{rtl160.bpl } System.Classes.StdWndProc (Line 13878, "System.Classes.pas" + 8) + $0
[503372F3]{vcl160.bpl } Vcl.Controls.TWinControl.WndProc (Line 9976, "Vcl.Controls.pas" + 152) + $6
[5035A413]{vcl160.bpl } Vcl.StdCtrls.TCustomListBox.WndProc (Line 6918, "Vcl.StdCtrls.pas" + 55) + $5
[503325D0]{vcl160.bpl } Vcl.Controls.TControl.Perform (Line 6982, "Vcl.Controls.pas" + 10) + $8
[50337443]{vcl160.bpl } Vcl.Controls.DoControlMsg (Line 10045, "Vcl.Controls.pas" + 12) + $11
[50337FF6]{vcl160.bpl } Vcl.Controls.TWinControl.WMDrawItem (Line 10371, "Vcl.Controls.pas" + 1) + $8
[50332995]{vcl160.bpl } Vcl.Controls.TControl.WndProc (Line 7204, "Vcl.Controls.pas" + 91) + $6
[50337382]{vcl160.bpl } Vcl.Controls.TWinControl.DefaultHandler (Line 10004, "Vcl.Controls.pas" + 17) + $10
[50332995]{vcl160.bpl } Vcl.Controls.TControl.WndProc (Line 7204, "Vcl.Controls.pas" + 91) + $6
[5003CF1C]{rtl160.bpl } System.TMonitor.CheckOwningThread (Line 14411, "System.pas" + 2) + $0
[5003D222]{rtl160.bpl } System.TMonitor.Exit (Line 14600, "System.pas" + 9) + $7
[5003D25B]{rtl160.bpl } System.TMonitor.Exit (Line 14614, "System.pas" + 2) + $7
[50313723]{vcl160.bpl } Vcl.Graphics.FreeMemoryContexts (Line 7043, "Vcl.Graphics.pas" + 12) + $8
[50336948]{vcl160.bpl } Vcl.Controls.TWinControl.MainWndProc (Line 9689, "Vcl.Controls.pas" + 3) + $6
[5033695D]{vcl160.bpl } Vcl.Controls.TWinControl.MainWndProc (Line 9692, "Vcl.Controls.pas" + 6) + $0
[20F90B36]{designide160.bpl} DeskUtil.SetFocusHook (Line 462, "DeskUtil.pas" + 4) + $C
[503372F3]{vcl160.bpl } Vcl.Controls.TWinControl.WndProc (Line 9976, "Vcl.Controls.pas" + 152) + $6
[50336948]{vcl160.bpl } Vcl.Controls.TWinControl.MainWndProc (Line 9689, "Vcl.Controls.pas" + 3) + $6
[500B6890]{rtl160.bpl } System.Classes.StdWndProc (Line 13878, "System.Classes.pas" + 8) + $0
[503373F0]{vcl160.bpl } Vcl.Controls.TWinControl.DefaultHandler (Line 10017, "Vcl.Controls.pas" + 30) + $17
[503375F4]{vcl160.bpl } Vcl.Controls.TWinControl.PaintWindow (Line 10100, "Vcl.Controls.pas" + 9) + $6
[503374A9]{vcl160.bpl } Vcl.Controls.TWinControl.PaintHandler (Line 10060, "Vcl.Controls.pas" + 4) + $14
[50337CA8]{vcl160.bpl } Vcl.Controls.TWinControl.WMPaint (Line 10261, "Vcl.Controls.pas" + 6) + $5
[5044A021]{vcl160.bpl } Vcl.Forms.TCustomForm.WndProc (Line 4344, "Vcl.Forms.pas" + 201) + $5
[503325D0]{vcl160.bpl } Vcl.Controls.TControl.Perform (Line 6982, "Vcl.Controls.pas" + 10) + $8
[5035A81C]{vcl160.bpl } Vcl.StdCtrls.TCustomListBox.WMPaint (Line 7094, "Vcl.StdCtrls.pas" + 6) + $6
[50332995]{vcl160.bpl } Vcl.Controls.TControl.WndProc (Line 7204, "Vcl.Controls.pas" + 91) + $6
[50037A80]{rtl160.bpl } System.@GetMem (Line 3454, "System.pas" + 20) + $0
[5003E65E]{rtl160.bpl } System.@NewUnicodeString (Line 19030, "System.pas" + 10) + $0
[5003E8A9]{rtl160.bpl } System.@UStrFromPWCharLen (Line 19713, "System.pas" + 28) + $0
[5003FFB0]{rtl160.bpl } System.@UStrCopy (Line 24873, "System.pas" + 18) + $A
[50069CEC]{rtl160.bpl } System.SysUtils.ChangeFileExt (Line 8475, "System.SysUtils.pas" + 3) + $E
[50069CF9]{rtl160.bpl } System.SysUtils.ChangeFileExt (Line 8475, "System.SysUtils.pas" + 3) + $1B
[50069D0E]{rtl160.bpl } System.SysUtils.ChangeFileExt (Line 8476, "System.SysUtils.pas" + 4) + $10
[503372F3]{vcl160.bpl } Vcl.Controls.TWinControl.WndProc (Line 9976, "Vcl.Controls.pas" + 152) + $6
[5003D50F]{rtl160.bpl } System.TMonitor.TryEnter (Line 14790, "System.pas" + 10) + $0
[5003D078]{rtl160.bpl } System.TMonitor.Enter (Line 14489, "System.pas" + 4) + $2
[503372F3]{vcl160.bpl } Vcl.Controls.TWinControl.WndProc (Line 9976, "Vcl.Controls.pas" + 152) + $6
[5035A413]{vcl160.bpl } Vcl.StdCtrls.TCustomListBox.WndProc (Line 6918, "Vcl.StdCtrls.pas" + 55) + $5
[50336948]{vcl160.bpl } Vcl.Controls.TWinControl.MainWndProc (Line 9689, "Vcl.Controls.pas" + 3) + $6
[500B6890]{rtl160.bpl } System.Classes.StdWndProc (Line 13878, "System.Classes.pas" + 8) + $0
[5033A151]{vcl160.bpl } Vcl.Controls.TWinControl.Update (Line 11961, "Vcl.Controls.pas" + 1) + $12
[5033A169]{vcl160.bpl } Vcl.Controls.TWinControl.Repaint (Line 11967, "Vcl.Controls.pas" + 2) + $4
[5033171E]{vcl160.bpl } Vcl.Controls.TControl.Refresh (Line 6445, "Vcl.Controls.pas" + 0) + $2
[21118327]{vclide160.bpl} PropBox.TCustomPropListBox.ItemsChanged (Line 530, "PropBox.pas" + 3) + $2
[500A77ED]{rtl160.bpl } System.Classes.TStringList.Changed (Line 6121, "System.Classes.pas" + 2) + $7
[500A7DCF]{rtl160.bpl } System.Classes.TStringList.SetUpdateState (Line 6375, "System.Classes.pas" + 1) + $14
[500A5D6D]{rtl160.bpl } System.Classes.TStrings.EndUpdate (Line 5406, "System.Classes.pas" + 1) + $A
[21119E0F]{vclide160.bpl} PropBox.TCustomPropListBox.AdjustItem (Line 1311, "PropBox.pas" + 66) + $9
[21120052]{vclide160.bpl} IDEInspListBox.TInspListBox.WMLButtonDown (Line 1560, "IDEInspListBox.pas" + 21) + $10
[50332995]{vcl160.bpl } Vcl.Controls.TControl.WndProc (Line 7204, "Vcl.Controls.pas" + 91) + $6
[503369DD]{vcl160.bpl } Vcl.Controls.GetControlAtPos (Line 9712, "Vcl.Controls.pas" + 4) + $13
[503372F3]{vcl160.bpl } Vcl.Controls.TWinControl.WndProc (Line 9976, "Vcl.Controls.pas" + 152) + $6
[5003D50F]{rtl160.bpl } System.TMonitor.TryEnter (Line 14790, "System.pas" + 10) + $0
[5003D078]{rtl160.bpl } System.TMonitor.Enter (Line 14489, "System.pas" + 4) + $2
[5003CF1C]{rtl160.bpl } System.TMonitor.CheckOwningThread (Line 14411, "System.pas" + 2) + $0
[5003D222]{rtl160.bpl } System.TMonitor.Exit (Line 14600, "System.pas" + 9) + $7
[5003D25B]{rtl160.bpl } System.TMonitor.Exit (Line 14614, "System.pas" + 2) + $7
[50313723]{vcl160.bpl } Vcl.Graphics.FreeMemoryContexts (Line 7043, "Vcl.Graphics.pas" + 12) + $8
[50336B88]{vcl160.bpl } Vcl.Controls.TWinControl.IsControlMouseMsg (Line 9753, "Vcl.Controls.pas" + 9) + $25
[503372F3]{vcl160.bpl } Vcl.Controls.TWinControl.WndProc (Line 9976, "Vcl.Controls.pas" + 152) + $6
[5035A413]{vcl160.bpl } Vcl.StdCtrls.TCustomListBox.WndProc (Line 6918, "Vcl.StdCtrls.pas" + 55) + $5
[50336948]{vcl160.bpl } Vcl.Controls.TWinControl.MainWndProc (Line 9689, "Vcl.Controls.pas" + 3) + $6
[500B6890]{rtl160.bpl } System.Classes.StdWndProc (Line 13878, "System.Classes.pas" + 8) + $0
[50454598]{vcl160.bpl } Vcl.Forms.TApplication.CancelHint (Line 10993, "Vcl.Forms.pas" + 6) + $7
[50453213]{vcl160.bpl } Vcl.Forms.TApplication.ProcessMessage (Line 10164, "Vcl.Forms.pas" + 23) + $1
[50453256]{vcl160.bpl } Vcl.Forms.TApplication.HandleMessage (Line 10194, "Vcl.Forms.pas" + 1) + $4
[50453595]{vcl160.bpl } Vcl.Forms.TApplication.Run (Line 10332, "Vcl.Forms.pas" + 26) + $3

May be that helps you to get an idea of the error source?
We're planning to purchase Instrument-/PlotLab for our Institute, but we want to solve this problem first.
Thanks in advance!