wireless client authentication

I have a windows 2003 domain with a Windows 2003 server
machine that is PDC for domain.
All desktop clients equipped with Windows XP Pro and
Ethernet card 10/100 Mbps join to domain without problems.
When i attempt to connect to the same domain with a
wireless desktop client equipped with Windows XP Pro -
Service Pack 1 and Wireless PCI Card 22Mbps US Robotics it
don't join correctly to domain.
The wireless client is configured at the same manner than
others desktop client with LAN connection an from this
wireless client is possible to execute ping to the Windows
2003 Server.
It is correctly added to the DNS forward and reverse
lookup zones.
But, for that client, the group policies are not applied
and in the event viewer ther is "impossible to find valid
domain controller".
I repeat that is not a TCP/IP proble because ping
correctly work from the wireless client am the server.
I've tried to set in the properties of the wireless
connection of the client even "Network Authentication
shared mode" even "DAta encryption (WEP enabled)" and "The
key is provided automatically", but the result was the
same!
But the really incredible thing is that when i change
wireless desktop client with Notebook wireless client
equipped with a PCMCIA card 22 Mbps from the same
manufacturer (US Robotics)with the same settings it work
fine and no any proble there was.
There is anyone that can help me.
Thanks you.
Cosimo Mercuro

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