asterisk users - Apr 2013 - failed to extend from 512 to 676 on cli

Hello, We are using around 100 real time sip peers with phpagi. On asterisk cli,
getting frequent message 'failed to extend from 512 to 676'. Once we
execute 'sip reload', this message disappear for some time and then
comes back. Please let us know the solution for this. asterisk version
1.6.2.9mysql 5.0server: Intel(R) Core(TM) i5-2500 CPU @ 3.30GHzRAM: 4 GB
Thanks,Kamlesh
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.digium.com/pipermail/asterisk-users/attachments/20130417/38a9eae2/attachment.htm>