When I run it, it continues indefinitely and slows my computer to a crawl.
How can you run it if it doesn't compile?
When I compile the rest of it and then paste that particular function into the REPL... I guess Willem's explanation shows why that worked.
Anyway, maybe you could put CHECK-SYSTEM-MESSAGES in messaging.lisp for the time being? I'll have a more thorough look at your code later...
Sounds like a good idea, but I will try to follow Faré's suggestion and create a separate process monitor. As Faré pointed out, my solution was too complicated. Hopefully I will have time to work this evening. For now I am busy with school.
Eric