Which AV do you both use CaptSopwith, Donik?
Here I use ESET AV and WOFFToolbox works fine. WSE is disabled totally.
Sometimes AV may block it even if if you exclude folders. it's also possible if it sees it as a threat (false positive) it may have been amended / "cleaned "by the AV program so even if the file is there may not work.
Seems some AVs dont like WOFFToolbox (again) we sent it tio Bitdefender and it should have been removed