Hi axispara
One possibility is the Google reCAPTCHA keys. Did you enter them correctly into that file? It should look something like:
Code:
$publickey = "TheRandomPublicKeyYouGotFromGoogleoS-B4dKonyqZjAbR76";
$privatekey = "TheRandomPrivateKey6Ld3itMSAAAAAPnf-B4dKo";
replace the bits between the "" with your our own keys that you got

Regards
David