[19-Aug-2013 15:01:55] WARNING: [pool www] child 543 said into stderr: 
"zend_mm_heap corrupted"

This error is due to a problem with the segmentation of the APC cache. If this error occurs, you may purge the APC cache. In the event that this error occurs frequently, then you can also deactivate the “garbage collector” by modifying the php.ini configuration file of the instance:

zend.enable_gc = 0