Confusing error in apache -

i trying resolve error apache returning:

[thu may 02 20:59:40 2013] [notice] child pid 10542 exit signal segmentation fault (11) [thu may 02 20:59:41 2013] [notice] child pid 10541 exit signal segmentation fault (11) [thu may 02 20:59:41 2013] [notice] child pid 10543 exit signal segmentation fault (11) [thu may 02 20:59:41 2013] [notice] child pid 10544 exit signal segmentation fault (11) [thu may 02 20:59:41 2013] [notice] child pid 10545 exit signal segmentation fault (11) [thu may 02 20:59:41 2013] [notice] child pid 10547 exit signal segmentation fault (11) 

when error happens, page aborted , not return message.

all happens when check session variable on page:

if (! isset ($ _session ['cartid'])) {} 

i found solutions on internet nothing worked.

if (! isset ($ _session ['cartid'])) {} 

try

if (!isset($_session['cartid'])) {}