Possible Duplicate:
PHP rsa get public key from pem file

Trying to verify received signature with following code.

$file = "C:\key_file.pem";  
$keypair = Crypt_RSA_KeyPair::fromPEMString(file_get_contents($file)); 
$public_key = $keypair->getPublicKey(); 
$rsa_pub_key = Crypt_RSA_Key::fromString($public_key->toString()); 
$rsa_obj = new Crypt_RSA; 
$verify_status =  $rsa_obj->validateSign($text,$recieved_signed_sign, $rsa_pub_key) ? 'valid' : 'invalid';

getting error as Fatal error: Call to undefined method PEAR_Error::getPublicKey() in C:\Program Files\xxxx\rsa.php