Integer under/overflowed

The system I’ve come across is running 1.2.26 through a marvellous trixbox installation. This has just happened. Can anyone point me in the right direction. No trixbox bashing though, I’m replacing it when I can.

Feb 12 11:22:27 NOTICE[4228] cdr.c: CDR on channel 'IAX2/FMGBRKVLE-12' lacks end
Feb 12 11:22:30 WARNING[4639] ast_expr2.y: Conversion of 0 to integer under/overflowed!
Feb 12 11:28:43 VERBOSE[4711] logger.c: Asterisk Event Logger Started /var/log/asterisk/event_log