Excel elapse time formula not working

I have one spreadsheet that was sent back by experts exchange basically taking a start and stop time and creating an elapse time.  I have attached that spreadsheet.  I am trying to find the elapse time with new data but the formula doesn't work on a different spreadsheet.  I have attaced both spreadsheets here.  The one that works has an extra column showing the elapse time - the one that doesn't work does not have that column.  When I copied and pasted the new data into the old spreadsheet it does not calculate either.  I need to understand what I am doing wrong.  Escalation-Performance-August-ex.xls August-appt-ctr-stop-escalation.xls