The Uptime test ran for five days against the test server. Then they asked to look at the list of transaction logs in the Admin app and the server app crashed hard. Since no one was logged into the server machine, the just-in-time debugger didn't fire, so there's no telling exactly where or why the crash occurred.
I have rewritten the code that retrieves the list of transaction logs, because it was a slow, inefficient little memory hog. Now it is faster and a good bit more efficient.
Unfortunately, it would probably require another five days of testing to verify that this particular problem has gone away.