It should throw an error if public_cert or private_key file paths are wrong.

[carbontwelve]

it took me a bit of playing around before I realized that the error:

Fatal error: Call to a member function get_name() on a non-object in /xero.php on line 784

Was being caused due to an incorrect path being given... would be nice if it had thrown an error at line 188 rather than just returning false.