Hi,
It means that you should copy Granny2.dll from D:OS to the directory of the extractor to be able to load these GR2 files. Unfortunately I cannot include this dll in the package for legal reasons.
Thank you so much! I actually did search for it in the game's folder before posting but didn't find anything. Just assumed I was doing something wrong, but its actually in the Divinity engine folder:
...\Steam\steamapps\common\The Divinity Engine\granny2.dll
