Encountered this error today trying to post a reply to Open Dialog & the Fonts Folder. At first I thought there was a problem with the site, but I was able to reply to a different thread. So I went back, and tried editing the message, a couple times, then it posted, but truncated it halfway into the second sentence (just plain text at that point, but there was code tags a little farther in). I went to edit again and basically re-wrote the post, and the whole thing finally worked completely. I lost the original post but the code sample and structure was the same, it was the same thing in different words.