|seems it can only be a corruption in Office|
You can try a Repair,
On the Powerpoint task bar, select the Help menu, click Detect and Repair.
Select Start, Control Panel
Under Programs, select Uninstall
Scroll down to the Office 2000 entry
Select, but do not double click,
At the top of the window, you should see the options to:
Uninstall, Change, or Repair
Click on Repair
See if that helps.