Interbase with Querys doesn't support exception handle?

Hi !

I'm working with Interbase tables, Query and UpdateSQL components
besides a master/detail tables.

My problem is that I can not understand (unless querys doesn't support
exception handle) the reason of this:

   DataBase.StarTransaction;
   try
     query.ApplyUpdates;
     DataBase.Commit;
   except on E: EDBEngineError do
      begin
          Errores.MyError(E);
          DataBase.Rollback;
      end;
   end;

Why Errores.MyError(E) is never executed if I make a
mistake(intentionaly) and query.ApplyUpdates raise an exception of class
EDBEngineError?

My Delphi has an unmarked option in Tools\De{*word*81} Options\Languaje
Exception\ Stop on Delphi exception.

Thank's in advance

RAH