Oracle Error Message
ORA-09842: soacon: Archmon unable to create named pipe.
Reason for the Error
mknod() failed to create named pipe ?/dbs/mon2arch_@.
Solution
Your current OS login may lack write permission for the ORACLE_HOME/dbs directory. Only userids in the dba group of a given instance can run archmon for that ORACLE_SID. Make sure that the ORACLE_HOME directory is correct in oratab.