Error: already exists previous definition

[Jan-Piet Mens]

> 20-Jul-2012 15:26:40.181 config: error:
> /var/named/etc/namedb/conf/zone_0.conf:1529: zone 'xxxxx.net':
> already exists previous definition:
> /var/named/etc/namedb/conf/zone_0.conf:1529
> 20-Jul-2012 15:26:46.270 general: error: reloading configuration
> failed: failure

That looks very suspiciously like a file which has been included twice.
Check again. And again. :)

> This has never ever happened before and the problem only started a
> few days day, and we did not make any changes to our BIND servers.

Are you quite sure? What are the modification times of named.conf and
*all files* it includes? [ls -l]

What does `named-checkconf' report?

Oh, and while you're at it, you should upgrade BIND -- the version you
are using is pretty old.

        -JP