Runtime error on changing themes and screen savers on Windows XP

I have issues in changing a few themes and screen savers on my Windows XP. Now I try to do a modification on my Microsoft Plus I get a runtime error message.
Error
A Runtime Error has occurred. Do you wish to Debug? Line: 54 Error: Function expected
I have not done any changes to my network nor to my environment. Has anyone come across the same error message?
I need help with the above error message.
