Is it possible that you are entering the "passphrase" and not the actual WEP key code? (if it is WEP.)
You might need a WEP Key Calculator...
http://www.csgnetwork.com/wepgeneratorcalc.html
The first thing I would try is to disable the password on your router to make it an open network. Try to connect to the open network with no password. This can help you to determine if your phone is the problem, or if your password is the problem. I had a simllar problem with a Nintendo DSi using a WPA2 passcode...It had to be converted into a big long hex code.
One more thing....are you absolutely sure that you are trying to connect to YOUR router? I notice in my part of town, my neighbors have 2WIRE933,2WIRE839,2WIRE393, etc...?
The fact that it tells you the network key is incorrect, causes me to really think that your 12 bit code is just a "passphrase" that needs to be converted to hex when you enter it into the TP2.
Can you get into someone elses router? Maybe try using BACKTRACK 4 to "sniff" your WEP key? This will give you the wep key in the hex format. Occasionally some routers are touchy, and wont take it in hex, and others won't take it in decimal. Some prefer to be on top.