I was finally able to find enough time to test this on my PC today, but I couldn't really reproduce it either with Pentaho CE 6.1 or 7.0.
If you are using the latest snapshot build, then the problem might be related to some specific differences in environment, as it's the exact same codebase I just tested.
From the stacktrace, I can see that it complains about not finding a Servlet context when its wrapper is destroyed. Maybe I should have put a null check there, but it doesn't look like the root cause for the problem you have, because the Servlet should not be destroyed while in use, at the first place.
So, I'd like to suggest you to check the error message again, and see if you can trace a different stack trace there, possibly above the one that you pasted. Or you can just delete all the log files and reproduce the problem once, and copy & paste the entire log messages to somewhere like pastebin.
Sorry for the late response!
Cheers,
Xavier
2016년 11월 16일 수요일 오전 11시 56분 29초 UTC+9,
tuga...@gmail.com 님의 말: