I had a problem the other day, three hours in to my CLD exam, where I had a broken run arrow but had no error messages. A colleague of mine experienced the same issue last night. I was using LV 8.0 and my colleague was using LV 8.2. I have seen several previous discussions about this but I did not see the solution we can to. In both my and my colleague's programs, we used the warning messages to find the problem was a tunnel with NO wires going to it. In my case, I had two tunnels stacked on top of each other, rushing to complete the exam I missed the tunnel when wiring to it so it created another tunnel, later while cleaning up the code I deleted the wire going to the hidden tunnel but the tunnel remained. This was not obvious since this tunnel was under another tunnel. I found a warning stating I had an unwired tunnel, should have been an error but it wasn't. Once I deleted the unwired, and hidden, tunnel the broken arrow cleared. I am not sure if this issue is know but I figured I would tell the LV world to check your warnings for unwired tunnels if you have a broken run arrow but NO errors. It may save you time and frustration, especially during the CLD Exam, in the future.
Happy Holidays, Merry Christmas, and all the other festive sayings.

AJL