I'm having the same problem at the download. I've seen other threads about a similar problem, but the suggested solution didn't solve my issue.
I was downloading 5 or 6 games and Witcher 2 was among them. The games that were before him on the list has downloaded typically and Witcher 2 started downloading and stopped at 11.15GB. Seems to be a bug of downloader, because the download of Witcher 2 is pausing and resuming intermittently.
I tried to solve putting Witcher 2 at the end of download list (I thought that it could be a temporary problem), but the others games downloaded with success and the Witcher 2 keep stuck at 11.15GB, blinking between paused and resumed.
Just closing completely the downloader and reopen it doesn't solve this issue. I hope someone can help me.
PS: I bought Witcher 2 in pre-release, and I downloaded successfully it still in 2011, I'm trying to download again because of the new patches.