Occassional Lockup, Full Version Fails to Install!?

Running Windows 7 64 bit.

Downloaded the sample version and managed to get it running. But on occasion, just before "cinematic" scenes occur, the game freezes. I exit and then restart the game, and usually the cinematics play. Why the freeze to begin with?

Downloaded the full version of this via BFG client / game manager. The download appeared to be OK, and validation also apparently OK. But then BFG client game manager says "Ready to install" and then BFG client / game manager seems to freeze (not responding). The full game does not appear to install!?

Waited literally about 10 minutes, and still nothing seemed to be happening, so I exited BFG client / game manager and then restarted it. But now BFG client / game manager wants to re-download the full version again!!? This is not very good as I'm on a slow internet connection; downloading this full version takes about one day!!

The BFG client / game manager is being run with administrator rights, so there shouldn't be an issue in that area.

Why will the full game version not install after downloading?