Well, just updating the status of this...
I had someone re-open port 5001 on the router and the slingox is working again.
So that's all it was.
Not sure what 'caused the router to close the port.
But, during the entire time, my slingbox status (http://support.slingbox.com/) was good,
and the "LastUpdated" field on my slingbox data from http://srs.slingmedia.com/getDeviceInfo.asp?id=
kept being updated, so my slingbox was talking to the slingbox.com server... but apparently not
through port 5001.
MY SUGGESTION to sling is they incorporate a port check in their status, to see if the
data stream port is open and working, since it's different from the communication port, apparently.
My own manual checks using: http://www.yougetsignal.com/tools/open-ports/
did show the port (5001) closed when it was not working, and now "open" after
it was re-opened at the router.
I'm back slinging...