For those with problems loging in do this:
1) Go to the location where Origin installed battlefield. This folder is called: "Beta Battlefield 3" (grave accent on first e). Now this is the problem; the Windows registry system can't cope with the 'e' with the grave accent, so change it to a normal 'e': "Beta Battlefield 3".
2) Next press the Windows key + r on your keyboard and enter "regedit" (without the "), press enter. Now navigate to: HKEY_LOCAL_MACHINE -> SOFTWARE -> Wow6432Node -> EA GAMES. Click on 'Bf3 Beta'. On your right you see a row of information where the 3rd and 4th row are filepaths, and there the annoying 'e' is back! Change the e's with the grave accent to normal 'e' in both filepaths and close the registry editor.
I had the same problem and now it works. I work with win7 64 bit so for the 32 bit windows the path is slightly different.