Same, OS, same game, same problem.
I took atioglxx.dl_ out of the 13.4 folder, added it to the W:ET folder and run ET (as admin, in xp, win7 win8 mode etc). It didn't change anything at all. Then I renamed the file to dll, but then et wouldn't even start and got me an error message like that was not a valid win32 file.
Do you know anything else that I could try? Got 13.12 installed.