I just setup the trial for Database Performance analyzer, and when I go to the webui, I get this message:
|Another DPA Server process is now controlling this Repository. In this case, either use the new IP address 'http://192.168.26.30:8123/iwc', or shutdown the other DPA Server process and try again. Contact your DPA Administrator if you have questions.|
The strange thing is, this isn't the IP address of the server, its actually not being used at all.
What you can do is shutdown the DPA server that you know of and then look at the repo connections. If you see the schema owner sessions still, note the machine they are coming from and shutdown that DPA server before starting up the new one.