Vista network names and problems

I have two Vista systems on a network with a Dlink DIR-615 router.

System 'A' can see and access 'B' with no problems. System 'B' can see 'A' in the Network Map but cannot access it. When on 'B', mousing over the symbol for 'A' does not change to a hand. When on 'A', mousing over 'B' changes to a hand and clicking opens an explore window for 'B'

As far as I can find, sharing on 'A' and 'B', in fact, all settings, are identical. All networks are set for 'Private'.

'A' is running SP2 Beta and 'B' is running SP1. I swapped the ports on the router and no change.

On 'A', the network name is Network 4 (automatically assigned) and on 'B' is Network 2.

Print and file sharing is on for both systems. Firewalls are set identically.

I'm running McAfee anti-virus and have their Easy Network running. 'A' can see the printers on the network but 'B' can only see the printer local to 'B'. 'B' can push a file to 'A' so there is some connectivity.

I'm stumped. Any suggestions.

 

Vista Network Additional Info

What I forgot to add was that my primary purpose is to share the printer on 'A' but that 'B' cannot see that printer. No resources on 'A' are available to 'B'.