SAP Note 15694 - OnArchive: Oncatlgr error ARC-E-01556, ARC-E-01250

Symptom:

Starting the ONCATLGR process for DB utility OnArchive causes the following error messages:
"Unable to initialize the IPC"
UNIX-E-00017, File exists
ARC-E-01556, mkfifo() error
ARC-E-01250, Error trying to test if catalog is already installed

Cause and prerequisites

To start the ONCATLGR process, it must be possible to write a UNIX named pipe (IX_ARC_CAT_V6.) to /tmp.
If a named pipe with this name already exists in /tmp, it must be overwritten with the same name. If the ONCATLGR process was previously started with user "root", the generated named pipe cannot be overwritten with the "informix" user, and the startup of ONCATLGR terminates with the above error messages.

Solution
Delete the named pipe that exists in /tmp:
(IX_ARC_CAT_V6.) and then call "start_oncatlgr" as user "informix".