I believe I've found the solution to this issue.
When burning a DVD DL disc you might encounter "Result Code = 5001" at the end of the burn.
The only reason why you would encounter this if you have unchecked verify disc before the burn and/or change eject or mount rather then ask or both.
I just left it to verify (rebooted) and ask me and I do not get "Result Code = 5001".
I burned 20 DL disc and did not have a problem with playing them even while getting "Result Code = 5001".
But please by all means prove me wrong on this.