"Invalid Pointer Operation" when creating data module

Question

I have a dll made in Delphi 2010, and sometimes there is "Invalid Pointer Operation" error when creating the data module, which contains dbexpress connection components (simpledataset, sqlconnection, clientdataset, etc, as well as some components of the rave report). The dll works 90% of the time, but sometimes generates the error.

The application that calls afunção da dll tb is made in December 2010. I researched a lot on google, but I’ve never seen this error when creating a data module, usually people find this error when giving one . free or when exiting the application, but in my case it is the CREATE data module.

I have tried to put Simplesharemem as 1a. uses declaration, both in the dll source and in the exe source that calls it, same error...

It occurs like this:

• application starts and calls DLL function, works normal, close the application
• application starts and calls DLL function, works normal, close the application
• application starts and calls DLL function, ERROR, close the application
• application starts and calls DLL function, works normal, close the application
• and so it goes...

The messages aren’t always the same, that’s what puzzles me:

• invalid Pointer Operation, OR
• error Reading sqlTable1FIELD1.Fieldname: invalid Pointer Operation, OR
• error Reading sqlTable1FIELD1.Sqlconnection: Property 0RAVECOMPLETED does not exist
• Class Tsmallintfield not found

Any suggestions?

function Imp1(vEmp: Integer): boolean; export; stdcall;
var Registry: TRegistry;
begin
  with dmNFD2 do
  begin
    try
      p_NumEmp := vEmp;
      result := True;
      if not(Assigned(dmNFD2)) then
         //Application.CreateForm(TdmNFD2,dmNFD2); // erro aqui ou
         dmNFD2 := TdmNFD2.Create(nil); // erro aqui
      if not(dmNFD2.sqlConn.Connected) then
      begin
        ConnectBD; // le o registro do windows (path, user e password database)
      end;
      if dmNFD2.sqlConn.Connected then
      begin
        qryGen.Close;
        qryGen.SQL.Text := 'select CAMPO from TABELA where PARNUM = :PARNUM';
        qryGen.Params.ParamByName('PARNUM').AsInteger := p_NumEmp;
        qryGen.Open;
        // insert or update in other table
        // ....
      end;     
    except
      on e:Exception do
      begin
        result := False;
      end; 
    end;
end;