Palin messed up.
Not nearly so much as this article suggests though.
Having read the link Josh gave (thanks Josh), it appears the only part of the story that isn’t in dispute is that she DID accuse the poor reporter guy of messing up, when he actually got the story correct.
That seems like a rather small error to make; maybe her staff also messed up by not moving her out of earshot, and away from the noise, so she could have the conversation — if they had, the reporter might have been able to explain it wasn’t him, and Palin would have apologized and there’s be no other reporter to confuse talking loudly in a crowd with “screaming”.
But I put that on par with the complaints about Bachmann’s staff not keeping her from getting a picture taken with a corn dog.