Can't attach files on network from Outlook

This is happening on two of the machines here. When attaching files in Outlook, the user tries to browse to the W drive (located Novell 4.11 server) Outlook stops responding as the directory structure appears. I was able to fix this problem on the machine a while back by re-installing Outlook. I have since tried a re-install of Outlook on another machine with the same problem but it didn't repair the problem. Is it worth re-installing again or is there some other problem here causing this?