the ?invalid=true query string variable means that one of the validations is failing.
To pinpoint which one, locate the following code:
if ($WAFV_Errors != "") {
PostResult($WAFV_Redirect,$WAFV_Errors,"contact");
}
and change it to:
if ($WAFV_Errors != "") {
die($WAFV_Errors);
PostResult($WAFV_Redirect,$WAFV_Errors,"contact");
}
this will write a coma separated list of numbers to the screen and help us determine which validation is failing.
Please post back a copy of your page so we can examine the code to determine the cause of the problem.