Can you be a lot more specific as to what's happening? What are you doing? What is the exact error message? Have you changed anything recently? Can you verify that your Subscription ID is correct?
JFBConnect will continue to operate just fine after you subscription expires. The subscription ID is required for the Autotune configuration and Error check tool, so if you've already run those, you shouldn't have any problems with the features of JFBConnect. Since your subscription still is active, you shouldn't have any issues at all. If you are though, again, please let us know more about what's happening.
Thanks,
Alex