MatthewHSE - 9:27 pm on Jul 5, 2010 (gmt 0)
I have a site where the server appears to choke on certain form submissions, but not all, when the data includes HTML. Sometimes I've been able to submit half the data, then half, then half, etc., until I narrow down the problem. Normally it's some word like "update" or something.
But sometimes it gets a lot more complex, as in all the chunks will go through individually okay, but won't go through as a group. I've never bothered to try to hunt out the root cause in those situations.
All that to say, it seems my shared host has some elaborate system of filtering taking place on submitted form data, before it ever gets to my scripts. You could be running into the same issue.
I'd suggest trying the trick of submitting half the data, then halving that, etc., to narrow down exactly what the problem is. When you find it, check with your host and see if they have anything going on that would cause the problems you're finding.