John_Marc -
I understand the code that you sent - thank you so much!

But, what I don't get is: how come the formprocessor works fine until I start checking for strlen or ereg?

This processor was cool because no matter what field you had in the form, it processed it and submitted all fields to the recipient.
Doesn't the code specify here:
while (list($key, $val) = each($_POST)) {
that it's a $_POST?