Name service error for <address>: Host not found, try again

I recently installed postfix because of problems with name lookups with
sendmail. Now I seem to get the same problems. This occurs whether or not
I use a smarthost. DNS seems to work OK with everything else. "postfix
check" gives no output.

Very sad - I like the look of postfix!

Is there some way of disabling name lookups for outgoing mail?? I'd like to
be able to check incoming mail to avoid spam.

Please note that "myserver.net.au" and "address.com.au" are hypothetical addresses.

debian:/etc/postfix# mailq
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
4514739D 279 Sun Sep 12 14:39:07 root@myserver.net.au
(Name service error for address.com.au: Host not found, try again)
robert@address.com.au

-- 0 Kbytes in 1 Request.

My main.cf:

debian:/etc/postfix# cat main.cf
# see /usr/share/postfix/main.cf.dist for a commented, fuller
# version of this file.

# Do not change these directory settings - they are critical to Postfix
# operation.
command_directory = /usr/sbin
daemon_directory = /usr/lib/postfix
program_directory = /usr/lib/postfix

smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
setgid_group = postdrop
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no
myhostname = debian
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = debian.myserver.net.au, localhost.myserver.net.au, localhost
relayhost = [203.220.32.149]
mynetworks = 127.0.0.0/8
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +

Output of nslookup:

debian:/etc/postfix# nslookup hotmail.com -sil
Server: 192.168.0.1
Address: 192.168.0.1#53

Non-authoritative answer:
Name: hotmail.com
Address: 64.4.32.7

My /etc/hosts:

debian:/etc/postfix# cat /etc/hosts
### etherconf DEBCONF AREA. DO NOT EDIT THIS AREA OR INSERT TEXT BEFORE IT.

127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

192.168.0.33 debian.mydomain.net.au debian mail.mydomain.net.au

### END OF DEBCONF AREA. PLACE YOUR EDITS BELOW; THEY WILL BE PRESERVED.

My resolv.conf:

debian:/etc/postfix# cat /etc/resolv.conf
domain mydomain.net.au
nameserver 192.168.0.1

My host.conf:

debian:/etc/postfix# cat /etc/host.conf
order hosts,bind
multi on