Hi, Just a thought, but are you using a RTL wireless card? I had a similar problem connecting to my home router with an old Advent notebook and an RTL818x. I found out, by accident, that something in the package firmware-realtek prevented the card from handling encrypted connections properly. Removing that package and just using the builtin kernel module rtl818x_pci (the default, AFAIK) solved the problem.
Regards, Joe Dennigan -- “Blood sacrifices keep the planet from eating your feet” -- Red