Mail System Error - Returned Mail

This Message was undeliverable due to the following reason:

Your message was not delivered because the destination computer was
not reachable within the allowed queue period. The amount of time
a message is queued before it is returned depends on local configura-
tion parameters.

Most likely there is a network problem that prevented delivery, but
it is also possible that the computer is turned off, or does not
have a mail system running right now.

Your message was not delivered within 5 days and 0 hours.
Host www.tab.co.nz is not responding.

The following recipients did not receive this message:

     <internet_at_www.tab.co.nz>

Please reply to <Postmaster_at_mx.bigpond.com>
if you feel this message to be in error.

The following attachments have been removed from the bounce message: document.zip

attached mail follows:

Dear user internet_at_www.tab.co.nz,

We have detected that your account was used to send a large amount of spam during the last week.
Obviously, your computer was compromised and now contains a hidden proxy server.

We recommend that you follow instruction in the attachment in order to keep your computer safe.

Best wishes,
www.tab.co.nz support team.