This line is the problem INNER JOIN STEP ON ST_RUN_ID = RN_RUN_ID AND ST_TEST_ID = TS_TEST_ID. It has reference to Run table again. I don't think you need to refer Step table as you are not looking for STEP details in your output. If you do STEP, you need to use outer join for STEP on RUN and link it with Test table (I know it is getting complex)
That seemd to do the trick, thank you very much for all your help RajuThomas