After re-reading through all of this thread, I'm wondering if the permissions here might be the problem. For the two posts showing the Oracle error, the message indicates that the tables can't be found. This is typically the case when the user account accessing the database can't "see" the tables because it does not have SELECT permissions on those tables or isn't assigned to a role that does either. This leads me to ask the question: which user account is embedded within your SDE connection files when connecting to the Oracle geodatabase via your script? Is it the SDE user, the schema owner (i.e., MDC or ARC), or some other user account? If it is not the schema owner that is attempting the delete operation, that could the the problem right there. Also, while the SDE user account should technically be able to see the tables, I don't think it would have rights to delete objects in another user-schema besides its own (unless the SDE user had a DROP ANY TABLE system privilege). So, could you check to see if the user account specified in your connection file is the data owner or something else?