Windows 98SE losing connection to server

I have a Windows 98 SE PC that is periodically losing it’s connection to a Windows 2000 server, the login is through Novell Netware for Windows. Sometimes it won’t map to the server when the 98 PC boots up. Other times clicking on the mapped drive in explorer or My Computer returns the message “e:\ is not accessible”. It seems to drop the connection after a period of time.