Sins of a solar empire, along with all of my other impulse games will not download via impulse. 
I've tried turning off AVG's firewall, resident shield, and web shield. I have 64 bit windows, but that shouldn't matter for downloading the game. It'll finish downloading the game completely but immediately after reaching 100 percent, it gives me the Download file invalid error. 
Solution: It was AVG's Link Scanner.
