Where is cn=subschemasubentry?

I have been unable to locate cn=subschemasubentry using ODSM. I thought at first that this would be due to the lack of permissions granted to my OID account, however, after having my OID administrator sign into ODSM, we weren't able to find cn=subschemasubentry using the orclAdmin account.
I need to find out where Oracle created their orclIDXPerson object class. LDIF script examples for modifying object classes always show the location of cn=subschemasubentry, but I all my LDIF script runs end with "Undefined attribute type is not supported in schema.: Attribute objectclasses":

TIA,
shastew