I realize this was posted a couple weeks ago, but it should be using "jobs" - with an S.
I just tried the service, using "jobs" and it properly queried the job.
I don't exactly understand how you've got that error. Is it when consumed in the FlexAPI? Like Flex is trying to get the status using JOB, or are you saying if you manually put URLS into your browser, it only works with JOB?