audit.rules "-e 2" not working

Issue

• I have RHEL5 installs and am trying to set the audit rules immutable with the "-e 2" option as the last line in /etc/audit/audit.rules.
  But when I restart audit with "service audit restart", it comes back with:

error sending enable request (Invalid argument)  
There was an error in line XX of the /etc/audit.audit.rules  

• If I run the command:

# auditctl -e 2  

I get

error sending enable request (Invalid argument)