Perhaps you are trying to set a breakpoint in the anonymous PL/SQL Block of the Test Script? You can only set breakpoints in stored program units, compiled in the database. In the anonymous PL/SQL Block of the Test Script, this is unfortunately not possible. You can create a simple "debug" stored procedure that can act as a placeholder for the anonymous PL/SQL that you want to debug, and create a standard test script to run it. This way you can make the process a little bit more efficient.