Hi,
I know this thread is kind of over, but I'm having the same problem.
I was having a similar issue before updating to the latest ipad software, but now that I have (trying to solve this issue) it's just made things worse and noe of the videos on my ipad have thumbnails.
The ipad needs to be taken to a meeting next tuesday and the blank icons look ugly...
I tried restarting and resetting the ipad as per the instructions in this post, I have restored the ipad using itunes and I have updated the software. none of this has worked and I have no idea what to do.
Help!