asterisk users - Jan 2007 - Unknown warning messages

Hi folks,

When my Sipura 2k is registered to Asterisk, I get some peculiar error
messages repeated in the logs every 30 seconds. I've put a snippet up in
 http://pastebin.co.uk/9067 for you to see. I don't have any complicated
setups. Just 2 sip.conf entries for the Sipura, and 2 more for
softphones. They can all register just fine, and I can make a call from
the Sipura to a test extension.

If anyone is able to provide some insight into this, it would be greatly
appreciated.

Regards,

Kyle