“no logon server” problem

I manage (barely) a small network of 50 pc’s hooked up to 2 Network servers. We run win 98v2 on all our pc’s and NT4 for our servers. We do not do a lot of file sharing but have started to do print sharing.Recently computers would ‘lose’ thier connection with the shared printer, when I have attempted to re connect, I would recieve the “no logon servers available to service your request’. The part that stumps me the most aside from not being able to find documentation for this , is that if I attempt to connect to a different printer, I may or may not get through this wall. . Anyway I have started to have this error message apear and cannot refrence any solution, is there someone out there who can help?