Characters are gone. Have unistalled and reinstalled several times.

I was playing over the weekend, had access to all my original characters. When I tried to log in today, I got a windows error telling me that the game was not designed to be run on windows. Unistalled everything, then reinstalled from Steam. Logged in, only had access to one character. Uninstalled again and downloaded from SWTOR.com, logged in, same issue. I have uninstalled and am reinstalling again. Also on a hopefully unrelated note, when logging in I still have the Onslaught load screen and not Dark Descent.