I did a lot of digging into this, I ended up speaking to both GoG and Larian support because I bought this game literally JUST for the toolkit.
From my conversation with Larian support, I gathered that GoG.com updates Divinity whenever patches come out, but they never updated the toolkit. Larian was not aware of this issue and suggested GoG update the toolkit download ASAP. Larian support told me that GoG would be updating the toolkit in the coming days (this was a week ago now). The old toolkit apparently doesn't work with the newer patches on Divinity.
I was impatient though and I asked GoG to refund the game (they did) so I could purchase it from Steam (I did).
Check the toolkit for updates though, it may be fixed you'll just have to re-download it.
Whether this info is credible or not, I don't know.
Last edited by Burgee; 04/11/14 06:24 AM.