This problem is documented in Cisco bug ID CSCdw74227.
If the max fd in /etc/system does not allow the aregcmd to work, this error message is received:
Logging in to localhost400 Login failedLogin to cluster 'localhost' faileddummy9i atls008 /opt/CSCOar/bin >
For a workaround,
Remove the max fd lines and reboot. Comment out the following lines in the /etc/system file: