Old problem. The patcher gets really angry if you rename ANY file. I renamed the "LoadingScreen.jpg" to "LoadingScreen.jpg.old" under "\Electronic Arts\BioWare\Star Wars-The Old Republic\swtor\retailclient\LoadingScreens", so it doesn't block my screen every freakin' time. But that causes this exact problem mentioned here. So I have to rename it every time to "LoadingScreen.jpg", until the new patch is applied.
Just give it (or any file you renamed) its old name and let the game patch again. It should work then.
I had not renamed anything, the only thing that I did do is delte the retailversion thingy file.. Now that I have it back it's fine again!