PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away

Whenever I try to enable the subscribe_node flag I get this error:

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away: SELECT r.rid AS rid, r.name AS name FROM {role} r ORDER BY weight ASC, name ASC; Array ( ) in user_roles() (line 2923 of C:\wamp\www\dev-arupconsult\modules\user\user.module).

The subscribe_user and subscribe_term flags work fine, but subscribe_node doesn't work