When using ibaPDA as an OPC server or client, the ibaPDA service must be run under the same user account as used by the OPC server. Perform the following steps to connect to ibaPDA with a local user account:

Open the Service Manager:
  1. Control Panel - Administrative Tools - Services 
  2. Select "ibaPDA service" and open the properties (double click) 
  3. Enable the "This account" option in the Connection tab and enter the defined account and password.
  4.  Restart the "ibaPDA service".