Roberto, Jason,

R> What I can say just now, is that the error is generated evey time
R> by the procedure TIBODataset.GetBookmarkData, the "Buffer" points
R> to an empty string and the line "B := Binary..." causes the
R> exception EAccessViolation,

<SNIP>

R> TIBODataset.GetBookmarkData(???,$245E240)
R> TIBODataset.InternalSetToRecord(???)
R> TIBODataset.Cancel
R> TIBOInternalDataset.SysCancel
R> TIB_Transaction.SysProcessCommitAction(True,False,False,False)
R> TIB_Transaction.SysRollbackBegin(???)
R> TIB_Transaction.SysRollback(False)
R> TIB_Transaction.Rollback
R> TDataMod.RollbackTr
R> TMainForm.CancelBtnClick(???)
R> TRxSpeedButton.MouseUp(???,[],???,18)
R> TSpeedbarButton.MouseUp(mbLeft,[],???,???)

I have what I believe could be the same problem, although my call
stack shows it gets there (GetBookmarkData) by a different path. I
have CachedUpdates and OnUpdateRecord added to the picture.

Jason: I got into this by applying your CalculateFields/GetCalcFields
patch, but unfortunately the test app is going well while the
production app fails. :-(

I'll try to duplicate the problem tomorrow in my test app and send it
back to Jason.

Roberto: it could well be that we are being bitten by the same bug. If
you have meanwhile succeeded in duplicating the issue please let us know.

Ciao
--
Nando mailto:nandod@...