the most likely culprit is validation.
find the following:
if ($WAFV_Errors != "") {
PostResult($WAFV_Redirect,$WAFV_Errors,"usersRegistration");
}
and change it to:
if ($WAFV_Errors != "") {
die($WAFV_Errors);
PostResult($WAFV_Redirect,$WAFV_Errors,"usersRegistration");
}
this will write a comma separated list of failed validations to the screen that we can use for troubleshooting, please post back this information.