Printer sharing over wireless

I'm trying to share a printer over a wireless network, but getting an access
denied message.

I have a desktop, fitted with wireless card, running windows XP 2nd edition
connected via USB to an Epson DX520

The laptop has built in wireless and is running Vista.

The internet and wireless router is via a sky broadband hub.

Both machines are running AVG home edition.

File sharing between machine works fine in both directions. The printer runs
fine from the XP machine. In the XP security settings it's set up to share
and given the share name 'Epson520' Using the laptop I can see the Epson
printer listed in the wizard, but when I select it to set it up as a shared
printer I get an 'access denied' message. Unfortunately there is no other
clue as to what the problem is.

Is the problem likely to be within Vista or AVG? Ideas anyone?