Php debugging - form to email

Have been using dodos mail to process a form submitted on a web site. Working until the beginning of the month. The ISP changed from PHP4 to PHP5 and the form no longer works. It displays a message saying that a required field has not been completed. (It has, and I have even taken out all references to required fields. Two options - debug dodosmail.php or find an alternative php form to email handler that will handle around 120 fields and email the form contents to one email address, with the originators email address, a subject line of "booking form" and then call another web page.

Can work with Skype or other screen share to resolve this with someone who is familiar with debugging or writing php code.

This needs to be done as soon as possible please.