I’m also a freehostia user and I’ve been having the EXACT same problem, and after seeing your post realized that it was probably a problem with them and not wordpress. Whether or not that’s true, I found a workaround and now I can see and edit plugins and do everything I could before the upgrade.
From your freehostia account login page, go to edit myphp settings and set it to myphp 4.0 instead of 5.0. That’s it. Now, I don’t know if that will cause problems for something else, but so far so good.