Linksys has flashed my t-mobile branded router model number WRTU54G-TM from v1.0.15 to v1.0.20 and in doing so broken all the port forwarding. I tried reflashing it back to v1.0.15 and that fixes the problem for a couple minutes before the vendor reflashes it to v1.0.20 again. The issue is that on the port forwarding page, the 192.168.0.[fill in] fields are now all filled in with the full path so you get 192.168.0.[192.168.0.123] where it used to have 192.168.0. and it doesn't work.
Okay, you can fix it by editing each of your entries to delete the extra 192.168.0. You have to do them all or it won't save and it complains the current values are invalid. As of today, there is no record of v1.0.20 on the internet since it was only released last Saturday and is not even posted on the linsys website yet. Supposedly, T-Mobile sent a text message to affected users, but I certainly did not get one and was going crazy thinking someone was hacking into my router to access my home network.