I was able to find a workaround. Bulk update a single story into the sprint --> reopen it. It was able to get me through the problem, but I would think this should become a defect / enhancement longer term since there is no reason that we shouldn't be able to reopen and empty sprint that is closed. I left a comment on JSWSERVER-7804 and my support ticket, but it is less of am impediment for me at this point.
The workaround is above, but they created a feature to be able to reopen a sprint with zero issues. Please vote for it if you would also like the feature: JSWSERVER-15859
Not being able to re-open an old sprint is really hamstringing us - we're converting to JIRA and we need the ability to move stories around for reporting - what a PITA.
