ms design tools invalid class string - error

i use windows XP WITH SP-2 , SQL SERVER 2000 WITH SERVICE PACK 4, VISUAL STUDIO 6 WITH SP5, .NET 2.0,

VS2005.

I AM CURRENTLY GETTING THE ERROR WHEN I USE ENTERPRISE MANAGER IN SQL SERVER 2000.

WHEN I SELECT A PARTICULAR DATABASE AND A TABLE, AND WHEN I SELECT THE DATABASE DIAGRAM AND TRY TO CREATE A NEW DATABASE DIAGRAM, I GET THE ABOVE ERROR