asterisk users - Mar 2010 - Asterisk crash - segmentation fault

My Asterisk 1.2.40 process crashes regularly in the is_zero_or_null function at:

return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));

My gdb trace is at:
http://pastebin.com/raw.php?i=hmhzZxye

Other examples here:
http://lists.digium.com/pipermail/asterisk-users/2010-March/245927.html

Can anyone please help?

--- On Tue, 3/23/10, Vieri <rentorbuy at yahoo.com> wrote:
> My Asterisk 1.2.40 process crashes
> regularly in the is_zero_or_null function at: 
> 
> return (*vp->u.s == 0 || (to_integer (vp) &&
> vp->u.i == 0));
> 
> My gdb trace is at:
> http://pastebin.com/raw.php?i=hmhzZxye
> 
> Other examples here:
> http://lists.digium.com/pipermail/asterisk-users/2010-March/245927.html
> 
> Can anyone please help?

And my Asterisk log shows the following right before the crash:

Mar 23 12:32:37 VERBOSE[9054] logger.c:     -- Executing
ExecIf("SIP/4070-09464648", "0|Set|REALCALLERIDNUM=4070") in
new stac
k
Mar 23 12:32:37 DEBUG[9054] app_macro.c: Executed application: ExecIf
Mar 23 12:32:37 DEBUG[9054] pbx.c: Expression result is '0'
Mar 23 12:32:37 DEBUG[9054] pbx.c: Function result is '4070'
Mar 23 12:32:37 DEBUG[9054] pbx.c: Expression result is '0'
Mar 23 12:32:37 DEBUG[9054] pbx.c: Expression result is '1'
Mar 23 12:32:37 DEBUG[9054] pbx.c: Expression result is '0'
Mar 23 12:32:37 WARNING[9054] ast_expr2.y: Conversion of 0 to integer
under/overflowed!

What does this mean?