error opening Enterprise manager

Greetings,
When I open up SQL Server 2000, I get the error:
"Run-time error!
Program: C:\Winnt\system32\mmc.exe
R6025
-pure virtual function call"
Any ideas what I need to do? I really appreciate it.
Thank you,
Jimuh reinstall sql client tools?|||Well, I did reinsatall SQL DMO 2000; is that what you mean, or do you mean something else.

I know there's SQL Server 2000 installation, and sqldmo2000 installation.

Is "sql client tools" something different?

Thank you,
Jim