Connection problem with MS SQL Server / Delphi 1.0

I'm using Delphi C/S 1.0, SYBASE Driver and MS SQL Server 6.0.
When I want to open more than one TQuery at a time, I get an
exeption EDBEngineError 'Connection is in use by another statement'.

This exeption seems to occur some other situations also.

Can anyone help me with this?

Olli-Matti Asikainen