Issues with rsh and kerberos

[Waldher, Travis R]

Ok.. 

[user at machine ~]$ rsh hostname -n uptime
krb_sendauth failed: You have no tickets cached
  9:35am  up 63 days, 19:33,  4 users,  load average: 0.76, 0.61, 0.56

Machine = RHEL client
Hostname = HPUX 11.11 client

I don't get the Kerberos error running this command against another RHEL
machine.

I have searched google and found nothing.  Anyone else have any ideas?