Thanks for the fast reply! I did this already and when it didn't work I went so far as to delete my old wunderground account and create a new account and re-entered the new account info 3 or 4 times with no success. I am now totally at a loss as to what to do next.
Unfortunately a new wunderground account might be complicating issues. Sometimes they take a while to get set up (about a day).
There's also the possibility that new wunderground station ID's may REQUIRE the the new station "key", but I can't confirm that. Some users have said only the newer "key" will work, but in my experience either the wunderground user password or key will work, at least for an existing station ID.