Resolution:
When starting the TIBCO Administrator service, the following error pops up.

<<<
2009 Jul 29 20:04:25:294 EDT Repository.gts_identitygtwy Info [Configuration] AEREPO-300011 Repository server "gts_identitygtwy" is ready.
java.lang.NullPointerException
        at com.tibco.pof.util.TempFileManager.a(TempFileManager.java:54)
        at com.tibco.pof.util.TempFileManager.deleteAllTempFiles(TempFileManager.java:47)
        at com.tibco.pof.util.TempFileManager.init(TempFileManager.java:31)
>>>

The error indicates there is some problem with cleaning up the temp files from the admin TEMP directory.

If you are using the machine system temp folder, please delete all the domain related temp files manually from the TEMP folder and restart the admin server.
If you are using the custom temp folder, (you can check if you have the property java.property.java.io.tmpdir in tibcoadmin_&ltdomianName>.tra),
please check if there is some problem with that custom temp folder. You can try to clean up that custom folder or recreate that folder, and then restart the admin server.