Hi Josh,
I have never seen this issue before so I am leaning towards a network issue on your end. Have you attempted to load the admin console in another other web browser? What about trying on another network (if possible)? What application server is this running on? I will keep searching for a possible cause but this is a pretty rare error. Also, if you could post the logs from your <jiveHome>/logs/ folder that could provide some insight. Thanks.
-Todd