SSL Certificate - Keytool Question

[3RiversTechAdmin]

Hey Everyone,

I have changed my host name so I need to make a new Certificate to reflect this (otherwise IE7 and Firefox complain about possible spoofing)
I was following the directions here:
http://wiki.zimbra.com/index.php?tit...icate_Problems
However, when I attempt to run:

root@XXX:/# /var/opt/zimbra/jdk1.5.0_08/bin/keytool -delete -alias my_ca -keystore /opt/zimbra/java/jre/lib/security/cacerts -storepass changeit

I get:

keytool error: java.lang.Exception: Alias <my_ca> does not exist

Should I be changing "my_ca" to my host name or something like that? Thanks.