There are a number of possible causes for this error message:
A database operation has returned the status of DB_BADOBJECT (see the nis_db man page for information on the db error codes).
You are trying to add or modify a database object with a length of zero.
You attempted to add an object without an owner.
The operation expected a directory object, and the object you named was not a directory object.
You attempted to link a directory to a LINK object.
You attempted to link a table entry.
An operation on a group object was expected, but the type of object specified was not a group object.
An operation on a table object was expected, but the object specified was not a table object.