I had the same problem. After the crash, a few players were affected by this problem.
For me, when connecting directly to HC my error box and menu tiles were all blank. I could connect to any other silent server without problems, when I connect to HC from another Silent server, I then see the menu tile text, and the text for the missing file errors.
pk3 cleaner wont work.
deleting silent versions won't work.
This will work:
Make a new install of ET 2.6b somewhere else on your harddrive. Save your original etkey. Replace your existing etmain folder with the folder from the new install. now put your original etkey into the new etmain folder that you just placed in your original ET installation folder.
Now you should be able to connect direct to HC, connect through XFire, etc.. without problems.