I have the exact same problem.
What i can see is that the files from the download folder do not get copied to the DCS World OpenBeta folder.
I tried to manually move, which worked, however, when repairing, it starts to copy everything into the downloads folder again, and...
When i do the repair function, it should download 6.2gigs, it is now at 14.7 gigs...
Doesn't seem right to me...