Cannot find file..

Cannot find file…” & docs disappear
I receive an error “cannot find file ‘/idlist,:508:xxx,\(where xxx=each time different number ex. 252; 1092; etc.), make sure the path and filename are correct and that all required libraries are available” when ever a user logs on to the network.

user cannot see any computer with w98 and has problems with MSOutlook. Any solutions I’ve found in this forum haven’t me helped to resolve problems.
Have any ideas or is it bettter to make new installation?