1180 wireless usb adapter and 128 (104?) bit encryption

I've just installed a Linksys WRT54GS wireless router with my Dimension 8600 system. This allows a VPN connection, which my previous True Mobile 1184 router did not.

 

I now have a problem with an older computer (running Windows 98SE) that hooks into the network with a True Mobile 1180 wireless usb adapter. The network is set up with 128-bit WEP encryption. I have entered the encryption key (in hexadecimal) into the appropriate field in the Client Manager configuration utility for the usb adapter. The link status window shows the proper SSID and channel number, and shows 100% signal strength. However, I can't access the Internet from this computer, nor can I see folders that have been designated as shared on the other computer in the network.

 

Browsing through the Linksys knowledge base, I noticed a comment that 128 WEP encryption may not work with non-Linksys components due to the lack of a IEEE standard. Do I need to downgrade the encryption level to 60 bit so that the 1180 can tap into the network?

 

Two other possibly related questions:

 

The Client Manager for the 1180 refers to high ecryption (26 hexadecimal digits) as 104 bit rather than 128 bit. Anyone know why?

 

The configuration page has a field called "Key Index", for which the possible settings are 0, 1, 2, or 3. Does this have any bearing on the problem?

 

Thanks in advance for any insight.