Buffalo WLI-PCM-L11 WEP problems

I was previously using a Buffalo WLI-PCM-L11 (Melco) 802.11b card with a
Buffalo Air Station and successfully running with 64-bit WEP. As I posted a
couple of weeks ago, the router died, so I replaced it with a Linksys
WRT54G.

The WRT54G router/access-point works fine with 64-bit WEP with my laptop's
built-in 802.11b using the WinXP drivers(Orinoco).

It also works fine with WEP disabled with the Buffalo card in all machines.

However, it doesn't work with 64-bit WEP in that laptop using the built in
WinXP drivers nor in a separate Win2000 machine using Buffalo's client
manager and driver.

(Quick tests suggest the card doesn't work with WEP with a Belkin 802.11b
router/access-point either.)

Is this an issue anyone else has faced and solved?

Thanks

Julian