This has to do with your networks. By any chance, are you switching between networks (e.g. Wireless to DHCP, etc.?)
An easy work-around is to disable system-jmx-connector (search for system-jmx-connector and set "enabled" to false).
This is of course a work-around (assuming you don't have to see MBeans through something like JConsole) till you have figured out this networking problems. At least, it should get you going.
Thanks,
Kedar
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