Problems with PSN downloaded games?

I keep having problems with installing games I download from PSN, every time the game is finished downloading, when I go to install it, it reaches a certain percentage, then gives me an error. I looked up solutions to the problem, people say I have to rebuild the database on my ps3, redownload and install. It works sometimes, but it seems to be completely based on chance, and I don't want to go through that whole process every time I want to install a game. So is there a permanent solution to the problem? Should I replace my Hard Drive? Is it the ISP?