Hi there,
Hopefully Jason will check out your page more thoroughly, but it seems that there is redundant code on your page, left over perhaps from previous forms and validations that are no longer part of your page's functionality.
There are three blocks of WA Server Validations server behaviors on your page (and listed in your Sever Behaviours panel) - the first two blocks (SimpleRegistration_submit and PetReg_submit) no longer seem to relate to a current form.
I would wait for Jason to cast an eye over things, but in the meantime if you wanted to, you could back up your page, and try removing the first two blocks of validations from the server behaviors panel and again remove the 'mysql_free_result($Pet_Reg);' line from the end of your page, as before.