Windows XP/98 SMC Router WEP Security

I have an XP host connected to a SMC Barricade G router.
The remote 98 machine has a MS MN-730 wireless card
installed.
I can connect to the internet through the router
providing I use no security WEP. If I install 64 or 128
bit WEP on the router and key in the identical security
key on the MS card, the 98 machine cannot see the router
and cannot connect to the Internet.
The message indicates invalid key on the MS MN730 set-up
software. I have used a simple easy to remember key and
therefore, I am sure about keystrokes.

Any ideas?