Changetrustpw & windbind

I'm upgrading Squid proxy from 2.5Stable14 to 2.6Stable20, and Samba
from 3.0.14a to 3.0.30. I'm also upgrading the OS from Solaris 8 to
10. I use winbind to authenticate Squid users to a Windows domain. I'm
not running either smbd or nmbd, just windbindd

As per the squid/samba instructions, I've run the command '/usr/local/
samba/bin/net rpc -S DC changetrustpw' daily
in a cron job. I'm not really sure it's necessary, but it has never
caused a problem. However, on the new server,
when I run this command it breaks my trust with the domain controller.
Does anyone know why it might be behaving differently? Is running this
command even necessary? I can't seem to find a definitive answer.

-Mike