do a find and replace of:
[FORMREF]
and replace it with:
CheckoutWizard_NewFromBlank_Default
for example:
$MailBody = $MailBody . (WA_getSavedFormValue('[FORMREF]','First_Name'));
should be
$MailBody = $MailBody . (WA_getSavedFormValue('CheckoutWizard_NewFromBlank_Default','First_Name'));
if you can be a bit more specific on what other changes you are trying to make i can give details on how to implement them.