Nico,
I've sent you a copy of the .dll, but it seems unlikely at this point that the file itself is bad since you've already replaced it with a working copy from a colleague's machine. It's more likely being triggered by something else.
Can you create a new user and launch InDesign from that new account?
InDesign is very sensitive to badly made or corrupted fonts. You said you haven't installed any fonts recently, but that doesn't mean one of the old ones isn't bad. If you have the original media for all of your fonts, I'd try removing everything except the required system fonts, then seeing if ID will launch. If it does, you know the problem is one of the fonts, and I'd reinstall from the original media, rather than just copying back the old ones. Do it in groups and test in between.
The most common sources of badly made fonts are free font downloads, so I'd be most suspicious of those if you have any and want to try removing just a few fonts first to test.
Peter
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