According to Metalink, you are attempting to split an partitioned IOT table with a user that the table does not belong to...
Cut from Metalink...
. Run the split partition statement from the owning schema or
from user who is granted DBA privileges.
or 2. Grant the following privileges to the other schema:
System privileges: ------------------
CREATE SESSION ALTER SESSION UNLIMITED TABLESPACE CREATE TABLE CREATE ANY TABLE ALTER ANY TABLE DROP ANY TABLE SELECT ANY TABLE CREATE ANY INDEX