erm, have you tried soft resetting? i forgot to try this option on my 900C, and i was fiddling with it for hours.. i know it may sound trivial
, but i've never had to do it on my jornadas.
are you sure you setup dhcp correctly on your router? i didn't for the first time, and only fixed IP/DNS worked.. and they can be entered wrong too, check them.
if your laptop or PC w/e can use internet, then it is something else..