What are the tables starting with EVT_ , SM, SMP_ . How can I get rid of them?

A have application installed at a customer's site that uses Oralce 8.0.5. I was up there today and we noticed some tables in the database that should not be there.
These tables have names that start with the following: EVT_ , SM , SMP_ What are these? I think some are related to Enterprise Manager. Most of the tables have no data in them. I noticed them a few months ago and I dropped them but now they are back. What can I do to get rid of them?
 What do I need to shut off to ensure that they do not come back.

They do not use this instance of Oracle for anything other than my app and my app does nto use these tables.

Thanks,
  DOn Received on Fri May 18 2001 - 19:16:26 CDT