Yeah, I have the same issue. Someone else reported it and got the standard tech drone garbage, none of which was helpfull in the least.
I am running SWTOR Unleashed and thought that might be the problem, so I backed out of the program, used the regular patcher and still had no luck. After that I restarted my computer to clear anything that might have been cached, fired up the normal launcher and still got nothing.
I've tried their launcher fix tool with similar results. The launcher downloads all the files and then sticks at 0% installed.
I thought it might of been Unleashed too; just uninstalled it and then came back here. Will try again for the hell of it, but at least I know it most likely isn't that.
EDIT: Uninstalled SWTOR Unleashed and the other program that comes with it (ImDisk I think it's called? I don't remember), restarted my PC and it then installed properly.