Are you constantly creating new references to your queues by, for instance, using "Obtain Queue" in a loop?
Looking at my code I see I have the obtain queues inside the loops everywhere. I suppose I should have had the Obtain Queue outside the loop. I'll try changing that and setting it going again. It takes 8 hours to crash but I think that must be the answer.
No problem, I had exactly the same error when I used Obtain Queue inside some sub-vis which were inside a loop. I was able to get rid of the memory problem by passing a reference to queue instead of obtaining it continuously.