Subject SV: [IBO] no return message of error in contraint of type check
Author Magnus Johansson
> When the firebird provokes an exception of type check the ibobject now
> he does not return the type of produced error, with which it is not
> possible to know that contraint of type check to given the error

If you have the source to 4.6.Bc you can change line 8300 in IBODataset.pas
if ( ErrorMessage.Count > 5 ) then
if ( ErrorMessage.Count > 7 ) then

Rebuild and see if that helps.