hp laserjet p2055dn network problem

I am experiencing a problem getting my new hp laserjet p2055dn to work as a networked printer. I can print fine via usb. My girlfriend's laptop can print using printer sharing. But when I print via the router, the command arrives in the print queue, then just sits and sits and sits, sometimes eventually disappearing, but without leaving any error message.

I tried printing via the network (bonjour) using an old laptop running OS 10.5 and it printed with no problem.

I've installed the latest drivers from hp spec'd for 10.6.

It seems to me that this must be a problem with OS 10.6.4. Anyone else had this problem and found a way to resolve it?

Thanks in advance for any help!