According to the log snippet you posted it can't connect to port 10025:
Code:
Jun 7 14:11:12 server03 amavis[23792]: (23792-01) (!)FWD via SMTP: <Roger.Laskowski@caremark.com> -> <sbenz@computervoice.com>, 450 4.4.1 Can't connect to 127.0.0.1 port 10025, (Bad file descriptor) at (eval 56) line 145, <GEN5> line 3121., MTA([127.0.0.1]:10025), id=23792-01
Jun 7 14:11:12 server03 amavis[23792]: (23792-01) Blocked TEMPFAIL, [204.99.118.101] [204.99.118.101] <Roger.Laskowski@caremark.com> -> <sbenz@computervoice.com>
When you're on the Zimbra server can you telnet to that port at localhost? Any other errors in the log?