missing file in window Rundll32

Dear Sir;
I have a problem to use my window CD-Rom to copy some files from window98 to my system. I get the message that the file called Rundll32 is missing and the CD-Rom does not work.
I only have this problem with window 98 CD, and not with anyother CD’s.
This has resulted in not be able to use my Scaner.
B. Regards
Fadakar
fadakar@yahoo.com