Hi all
The way you have the print sharing is not ideal. I agree it should work, but a better and much more reliable solution would be to use a print server, about £30 from ebay. I have the netgear WGPS606, which shares 2 printers to 6 PCs, 2 macs and 2 iphones. It looks like a router, and can connect wired or wireless into your network. Has worked flawlessly for me for the last 4 years,
hope it helps. Don't buy windows 7 on all those PCs just to get printing via USB sharing working! The print server is the way to go.
high-flyer