For future convience reasons with this procedure it would be a good idea to add the following line to your "/.profile" file.
export PATH=$PATH:/usr/lib/
The default AIX errpt, log file is located in: "/var/adm/ras/errlog" to confirm this enter the following command:
# /usr/lib/errdemon -l <ENTER>
Error Log Attributes
--------------------------------------------
Log File                /var/adm/ras/errlog
Log Size                1048576 bytes
Memory Buffer Size      8192 bytes

#

To change the AIX errpt log name, type in the following:

# /usr/lib/errdemon -i /tmp/newlogfile <ENTER>
# 

Now verify your changes by once again typing in:

# /usr/lib/errdemon -l <ENTER>

Error Log Attributes
--------------------------------------------
Log File                /tmp/newlogfile
Log Size                1048576 bytes
Memory Buffer Size      8192 bytes