Eden - 2013-08-17

Environment in my PC:
Delphi 2009 + sp4
Open Dbexpress Ver. 2012 0724.
===
My table have a DateTime type field
When I try DeltaDS.Fields[i].NewValue in TDataSetProvider.OnBeforeUpdate

I get a Access Violation on line 894 "CustomClientDataSet_DataConvert(Self, Field, Source, Dest, ToNative)"
in DbxDBFix.pas

My code like below:
SQLTimeStame1 := VarToSQLTimeStamp(DeltaDS.FieldByName('XYZ').NewValue);

Why?