Yet another wi-fi mystery

[fpowledg]

My Touch (32GB, not jailbroken) is but 4 days old, and I'm having problems using wi-fi. (Linksys/Cisco WRT54G2 router, home network, two computers connected by Ethernet, 2 occasionally by wi-fi, 1 cell phone by wi-fi). I can connect the Touch when I use *no* encryption at all, but not when I use *any* (WPA, WPA2, WAP128). I see that others have lots of wi-fi problems; has anybody had this specific one? I certainly don't want to walk about with my unprotected wireless connection hanging out.