The SERVNAK error means you may have lost one of your subscriptions while zwgc was loading your subscriptions as it starts up. SERVNAK stands for "SERVer Negative AcKnowledgement". Usually, just re-loading your subscriptions will fix the problem, and regain any subscriptions that you might have lost. To reload your subscriptions, type the following at the athena% prompt:
This error also comes up when you try to attach a locker and your Kerberos tickets have expired. If that is the case, type:
Then try re-attaching the locker.