Error on StoredProcedure with resultset on Close

[teimue]

Hello,
I'm using Delphi5 and Delphi2007 + Firebird2.1 + ZEOS6.6.6 Stable
I have a DLL written in Delphi2007 that makes a call of a stored procedure with resultset

Code: Select all

 with dm.zspGETLCIDSTRING do
      begin
         //close;//this position doesn't work
         ParamByName('LCID').AsInteger := ALCID;
         ParamByName('IDSTRING').AsInteger := AIDString;

         try
            open;
            S := dm.dsGETLCIDSTRING.DataSet.FieldByName('STRING').AsString;
            close; //this position works
         except
            dm.zcDB.Rollback;
         end;
         dm.zcDB.Commit;
      end;

The position of Close doesn't matter if I call the DLL with a program written in Delphi2007. But when I call the DLL with a program written in Delphi5 then I get an error if Close ist above Open. However not at the first call but after a lot of calls (ca. 1000)
In some code examples there is the Close above Open.
Has anyone any idea what is wrong?