Try deleting all of the files in the '..\Divine Divinity\Run\Dynamic' folder.
This folder is used as a cache for the game. Files are created / copied there from the save game folder when you load, and written / copied from that folder when you save a game. The files will be re-created as required the next time you start the game. If there was a corrupt file in that folder, deleting the files should fix the problem.
Now run Divinity, start a new game and see if the map works properly. If a new game works but your original does not, there is something wrong with your saved game. If a new game does not work, there may be something wrong with Divinity itself. In this case, re-installing the game may help. At least one other person had a sort of similar problem which re-installing did not help, and had to refrain from zooming the map all the way out.
If you want to try re-installing the game, zip or otherwise backup your saved games folder to another location first, just in case. Then un-install, re-boot, shut down all non essential programs (especially anti-virus), re-install the game, perhaps start the game and see if the problem persists (usually not necessary, but would help identify problems cause by the patch), re-boot, shut down all non essential programs, install the patch, re-boot, shut down all non essential programs, start the game. This procedure is a bit over-cautious, but the best way to avoid install problems.
