[Buzpilot]

I had a problem downloading a predownload, even after it's release. A tip on steam forum helped me, it was to delete 'ClientRegistry.blob' in steam folder, and reinstall, or repair it, then it downloaded immediatly after restart.
If it's persistant, it could help do this.

Edit; If you deleted steam folder before you reinstalled the first time, this probably wont help, but usually people don't delete folders when they reinstall.