Ms-Powerpoint 97 error message

I’m running on Win95 and Ms-Office 97.My Powerpoint is facing problem when each time I
click on OPEN file to search for my desire pps file but unfortunately after click once to
preview my pps file,it display out this error message “unexpected IO error 6 occur”.All my
pps encountered this problem but if my pps execute directly from Windows this kind of problem
doesn’t happen and my powerpoint slide show display beatifully..
I had reinstalled my Ms-office 97 before .Pls advise.