Try changing this in admin.php:
if(!function_exists('valid_email')){
function valid_email($xe) {
if(strpos($xe,'\\')===true) return false;
if(ereg("^[\._a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.([a-z]){2,4})$", strtolower($xe))){
return true;
} else {
return false;
}
}
}
To this:
if(!function_exists('valid_email')){
function valid_email($xe) {
if(strpos($xe,'\\')===true) return false;
if(ereg("^[\._a-z0-9'-]+(\.[_a-z0-9'-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.([a-z]){2,4})$", strtolower($xe))){
return true;
} else {
return false;
}
}
}
I have updated the code for future releases.
Regards