If you are using NServiceBus in a web application and the process named w3wp.exe keeps bombing and exiting shortly after starting, here's what's happening: You don't have the appropriate permissions set for your message queues.
The way NServiceBus is designed, it performs a few small startup tasks when the bus is started during web application initialization. Among these tasks it checks the configured input queue. If, because of a permissions error, it fails to read from the queue, it logs a message using the configured logging, waits 10 seconds, and then exits the process.
The simple fix is to give the web account permissions over the resource. This all goes back to one of my previous posts on the same subject, but I just wanted to mention that I got bit again because my message queue permissions were a little too tight.