Computer Error Message Fix needed. I have Windows 98 but upgraded to Windows XP and MSN wouldn't work so I uninstalled Windows XP and returned to W-98. Ever since I have been getting an error message that pops up constantly. It says: One of the library files needed to run this application cannot be found. UNICOWS.DLL I tried PC Doctor and paid a fee for a fix that did not fix anything or at least not the problem.