how to start the oms service??? -----------ERROR!

[oracle@localhost oracle]$ oemctl start oms
OEMCTL for Linux: Version 9.2.0.1.0 Production
Copyright (c) 1998, 2002, Oracle Corporation. All rights reserved.
Starting the Oracle Management Server...
Could not connect to the OMS: possible error in the configuration file.
Terminated
[oracle@localhost oracle]$


WHY???