you are using the password stored in the wireless router ?
i know im stating the obvious but ???
what router are you using.
if its a d-link (dir-301 ??? )
in the wireless network settings i had to tick 802.11g only mode and save before it would let me see my router and then connect .
try to set a wep key for your tablet only
i can use up to 4 separate keys
also use the lowest security settings first and then when connected try to improve your security level until your at the highest settings you can use.