Hi - This is an issue that has been hounding me for a couple months. I make my own contact forms using a PHP script which redirects the submission back to the current page. That way the user hits "submit" and the same page says "thank you very much".
I've used this on many WP sites, but after a recent upgrade (at least I think that was the issue), I can never make this work. The submission always redirects to an error page (can't find). It appears to me to be a real bug but I can't find anyone talking about it. (more likely not a bug, but just something I don't get about how WP works)
BTW, I've used the script on non-wp sites and it performs as expected. I really need some input on this, as I really like my little form submission script and use it all the time.
For and example, go here: http://www.intuito.biz/get-a-bid/