I am having Oracle linux relase 4 x86 32 bit and i have install Oracle EBS R12.1.1
after ebs installation completed seccessfully i am unable to change the users after loging with root,

the error is su: cannot set groups: Operation not permitted

the ownership of many direcoties has change from ( root ) user to ( Oracle user )

Any help

Oracle may be using selinux or linux capabilities to restrict changing file or group ownership. CH_CHOWN will restrict even root from using chown or chgrp. Selinux can protect particular areas from having ownership changed.

A directory with oracleuser ownership probably should be left alone. It may be configured to protect you from yourself.

You will need to provide more details on what directories you are trying to change. Also Oracle customer support might be able to clear up any questions on which areas you shouldn't mess with for the database to work.