BTW, that's not quite exact

I just screwed a title too (of another thread of course) and edited it myself. I admit, it was little bit cumbersome, but not too bad. So just for the records and the archive:
- Click Edit at the post, change to advanced mode - you can change the title / subject above the post first (it won't change the thread title though, but you want to fix it there certainly too)
- In the thread view, click Move / Copy Thread in the Thread Tools drop-down menu, edit the title and move it to another folder without letting a link (first selection Move to destination forum).
- Since it won't let you renaming the thread in the same folder, you have to really move it to another forum, and then repeat the operation, moving it back to the original location.
Normally it is rather quick, but currently there seem to be some problem with the forum (or maybe just on my side) and it hangs for about 10 minutes after each page load, before the status bar clears and the drop-down menus become active. I hope it just a temporary problem though.