Vista - Wireless LAN

I installed vista beta 2 on my laptop; it's a dual boot with winxp.
This is how I connect to the internet:
On another pc internet comes in. On that pc I installed a wlan card and so I
set up a wireless network with shared internet connection.
When I'm in my room running XP, there is no problem at all connecting to the
internet.
When I'm in Vista, I can connect to my local network, but not to the
internet... the status is 'local only'. When I stand with my laptop next to
the pc that is sharing the internet connection, there is no problem
connecting to the internet.
So it seems that there is a better range in XP than in Vista or something...
Does anybody know how I can get a better connection, like in XP?
On my laptop I have an Intel PRO/Wireless 2915ABG Network Connection.
thx!