The WildTangent download may already be updated to the latest version. What is the version number listed in the bottom right corner of the main menu? The second patch has a game version of 1.4.9.70 (the version number remained the same with the
Dragon Knight Saga DRM free patch).
There was no update to DKS after the DRM was removed, so if you never needed an activation key, it is already updated.
There were some minor fixes and changes in the Developer's Cut release of the game, as well as an optional Developer Mode cheat window added.
For Win7, try right clicking on the Divinity2.exe executable, selecting Properties and switching to the Compatibility tab, then disable visual themes and desktop composition. That has helped a few people with graphical problems.
Have you checked for updated drivers, etc?