ORACLE HOME box should have the Oracle application install path.
When Installing Oracle iDataAgent make, sure that Simpana is installed with appropriate group that is part of the Oracle user account, or any other account with permissions set to read-write-execute.
User Account with administrative privileges to access the Oracle application.
On Unix clients, the user should be part of the user group assigned during the iDataAgent install. You can also use the operating system user account to verify the rights to perform all backup and restore operations for the associated Oracle instance.
On Windows clients, the user should be part of local administrator group and also part of the ora_dba group with read/write permissions on Simpana folder. You can use the Impersonate user account to verify the rights to perform all backup and restore operations for the associated Oracle instance.
Please also check if you use connect string and that is been added to commvault config.