W2K and ME client and printing on HP720C

I setup a W2K server with ISA and use W2K clients and ME clients. On the W2K server I connected a HP 720C printer. Now the W2K clients can print on that printer, but the ME (and also 98SE) clients cannot use this printer. Both the server and the clients use the same printerdriver from HP. In the printqueue I see the job, but it gets flushed or something, because the job is not printed. Anybody coped with this problem before????