Why I get error “CoInitialize has not be

Currently I develop web based application (ISAPI) using websnap in delphi 6 and I facing the problem when I using ADO component in Delphi6 which is TADOQuery to accesing data in SQL Server 7 during runtime which is get error “CoInitialize has not been called” but fine in designtime.Can somebody let me know what’s caused the problem as soon as possible?
Currently I using IIS Web Server for develop web
based application.Thank You.