This issue occurs due to the presence of Cisco bug ID CSCsc81236.
This problem occurs in Cisco PIX or Adaptive Security Appliance (ASA) version 7.0.4. This problem can occur with or without the configuration of the inspect icmp error command.
As a workaround, either downgrade to PIX 7.0.2, or download and upgrade to PIX 7.1.1 or later.
Crashes / reboots / traceback
Network Address Translation (NAT)
Internet Control Message Protocol (ICMP)