Hmm darn. Thats a shame, Im almost out of options... a few more:
1. Is your phone rooted? From the picture, it doesnt apear to be, but i want to ask just in case.
2. Have you dropped your phone yet and does it have a case? I say this because a drop could damage the antenea, but ive never heard of that happening, but of course it is possible. Also, water damage could also cause this.
3. I highly doute it is those above two options, because all other sites work on your phone. So your third option is to take it to AT&T, or whatever your carrier is.
4. Im not familiar with how web pages work, but i could be possable that because your phone is so new that Facebook hasnt created a mobile site for it? Again, the more i think of if the more bullshit it sounds.
Sorry buddy, thats all I got. If something comes to me in the middle of the night then I'll get back to you, but as it stands your gunna have to go back to your carrier. Good luck!