That sounds like a bug - from what I'm told by a recruiter, you should be able to apply again by now. You can also start the process by emailing the address in the text at the bottom of job once you click on "Apply for this position".
Also, if you know somebody who works at Facebook, try to get them to refer you instead of applying directly. (Just email them your resume and ask if they can forward it.) This applies not just to Facebook but to most other big companies, especially popular employers that get a lot of resumes every week. Our recruiters try hard to evaluate all the resumes they receive, but if you guessed that they probably look more closely at ones that reach them by way of an internal referral, I think you guessed correctly.