Was doing a search on the same error (404 on post.php) when I found this thread =]
My coworker just had mentioned that sometimes mod_security on the serverside may recognize a request as spam and not serve the page at all as a precaution.
I was trying to post an article that referenced blogspot.com and it was rejected. After running the URL through tinyURL, it works. Go figure =/
If it is mod_security, you’ll just have to narrow it down to what link(s) it may be. Hope it helps.
