2013-06-15T11:00:04.408-05:00 [04944 warning 'ProxySvc Req14588 Tunnel'] Error on read from client: The specified network name is no longer available.
2013-06-15T11:00:04.408-05:00 [05056 warning 'ProxySvc Req14607 Tunnel'] Error on read from client: The specified network name is no longer available.
2013-06-15T11:00:04.408-05:00 [04232 warning 'ProxySvc Req14679 Tunnel'] Error on read from client: The specified network name is no longer available.
2013-06-15T11:00:04.408-05:00 [04076 warning 'ProxySvc Req14672 Tunnel'] Error on read from client: The specified network name is no longer available.
2013-06-15T11:00:04.408-05:00 [01508 warning 'ProxySvc Req14707 Tunnel'] Error on read from client: The specified network name is no longer available.
2013-06-15T11:00:06.124-05:00 [13136 info 'Default' opID=2549FF15-000000C9] [VpxLRO] -- BEGIN task-internal-534699 -- -- vmodl.query.PropertyCollector.retrieveContents -- 52a1e23c-375f-79e9-1d35-4efcfe32d9a6(52e16f89-64f4-cd83-9f08-1fca2be34063)
2013-06-15T11:00:06.124-05:00 [13136 info 'Default' opID=2549FF15-000000C9] [VpxLRO] -- FINISH task-internal-534699 -- -- vmodl.query.PropertyCollector.retrieveContents -- 52a1e23c-375f-79e9-1d35-4efcfe32d9a6(52e16f89-64f4-cd83-9f08-1fca2be34063)
2013-06-15T11:00:07.404-05:00 [05644 warning 'VpxProfiler'] VpxUtil_InvokeWithOpId [TotalTime] took 2964 ms
2013-06-15T11:00:07.996-05:00 [03788 warning 'Default'] Service control manager requested shutdown
2013-06-15T11:00:07.996-05:00 [03788 info 'Default'] Initiating VMware VirtualCenter shutdown
2013-06-15T11:00:07.996-05:00 [03788 warning 'Libs'] Failed to report event. Reason: The interface is unknown
2013-06-15T11:00:08.059-05:00 [03812 info 'Default'] Shutting down VMware VirtualCenter...
2013-06-15T11:00:08.059-05:00 [03812 warning 'Libs'] Failed to report event. Reason: The interface is unknown
Also check if the VC has network access? Has anything changed in networking?