This is the response I got on this issue:
I'm afraid this issue is most likely linked to the installed files and steam thinking all files are downloaded and ok.
Reinstalling on a different drive usually fixed this for most users.
I assume you have tried deleting the local files and installing it again?
Or installing it to a different folder on the same drive?
There is not much else we can do as the issue is most likely linked to corrupt or missing texture files.
This is the reply I sent back (on Sept. 2, 2014):
Thanks for the response. I don't have another drive to install Divinity: Dragon Commander to, just one hard drive ( C: ). I deleted the files and then reinstalled the game from Steam 3 times, verifying the integrity of the game cache each time (all files verified correctly). Also tried running as administrator. The ground textures for the game were black each time.
Out of desperation I even bought a 2nd copy of the game on www.gog.com, which was then installed on the C:\GOG Games\ folder instead of the C:\Program Files (x86)\Steam\ folder. However, the ground textures for Dragon Commander were black as well in the GOG version. All of my drivers are up to date and none of my other games have corruption problems, so I have no idea why it's happening.I haven't had any further info on this issue. It seems that there is no current fix for those running into it...