I usually have problems posting when using my iPod. If it's making the page scroll up to the top after you hit enter it's a glitch. If it's saying you reached the character limit when you haven't it's a glitch. If you're trying to post on someone's wall it could be privacy settings.
I can only post on walls on my iPad. I dunno why but I can't post on them on my PC or laptop. Its weird. Its probably a glitch with the site but its been like this for awhile. I have read that other users have been reporting similar problems to the fanpop team but still no change.
If its anything like me everytime i try to post the props or smiley face choices along with the submit or whatever it says does not show up on my pc and laptop but yet i can post on the same users wall that I was going to post on with pc or laptop on my iPad and everything shows up and it posts just fine.
Actually, I messaged Micheal (one of the creators of Fanpop) and he's fixing it right now. It could be the browser you're using or the "internet security" like Norton you may have. It might take awhile but I keep you updated.
