Problems connecting 802.11b laptop to 802.11g AP

I've just introduced a Linksys WAP54g access point into my network and added
Linksys wmp54g PCI Cards to 4 PCs -all of these can connect with no problem.
However, a Sony Vaio laptop with a built in Intel Wireless adapter cannot
connect.

The WAP has 128 bit WEP encryption enabled, is running in "Mixed" mode and
no MAC filtering is enabled. The laptop can "see" that the wireless network
is available and prompts me to connect to it. The adapter is using the
Windows XP wireless networking interface and I enter the 26 digit key in the
same way I did on all the other machines but it doesn't seem to be able to
get any further than this as it won't acquire an IP address.

Any one else come across this?

--
Grant

It's probably the Norton Internet Security Firewall blocking your
router from sending the IP address to the computer - it seems to cause
problems and disabling it rarely works. You might have to actually
uninstall it, but first try configuring it to allow network access to
the other computers on the network and the Internet.
Note: If you haven't setup Norton Internet Security yet, then for sure
that's the problem, as by default everything is blocked from entering
the computer through the NIC!