Problem printing to shared printer

I have a new WinXP system on a domain, that prints to printers on the print server, no problem. However, I have one printer on a Win98 workstation, that I have shared, and the WinXP workstation, when I first log on sees the printer and prints, then after a while, can not see the printer or the workstation. Cant figure out what the problem could be. I can print from other systems to the win 98 printer, and The Win XP can also print elsewhere. ANy ideas?