Windows installer faiilure

I run a network ofaround 80 win95/98 machines all running office 97.
I recently setup 8 new win 98 machine with office 2000. Now i have a problem that people loging onto the new machines and try to open an office program they get an error message as follows “The windows installer failed to install the program associated with this file.Please contact your system administrator.” If i then go in and delete them drom the users on that computer and also delete their user.dat file from the NT server they can then log in and use windows. Is this some conflict between off97 and off2000?