When sending a request to user.getbyid nothing is returned.

The following JSON object was sent:
{"jsonrpc": "2.0", "method":"user.getbyid", "params":

{"userid":1}

, "id":1, "auth":"nelsonab"}

Looking at the apache logs the following information is found

[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP Fatal error: Call to undefined function get_user_by_userid() in /var/www/html/api/classes/class.cuser.php on line 344
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP Stack trace:
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 1.

{main}

() /var/www/html/api_jsonrpc.php:0
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 2. CJSONrpc->process() /var/www/html/api_jsonrpc.php:53
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 3. CJSONrpc->execute() /var/www/html/api/rpc/class.cjsonrpc.php:58
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 4. czbxrpc::call() /var/www/html/api/rpc/class.cjsonrpc.php:106
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 5. call_user_func() /var/www/html/api/rpc/class.czbxrpc.php:53
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 6. czbxrpc::user() /var/www/html/api/rpc/class.czbxrpc.php:0
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 7. call_user_func() /var/www/html/api/rpc/class.czbxrpc.php:92
[Sat Sep 19 15:27:23 2009] [error] [client 192.168.1.191] PHP 8. CUser::getById() /var/www/html/api/rpc/class.czbxrpc.php:0