If you think that it is an authentic error, then you have to start your troubleshooting by asking yourself when did this start to occur and were there any hardware failures/issues around that time, e.g. failed disk, disconnected cable, etc...
You could also start by eliminating other causes. Firstly I notice that you are several build behind. You should really get to latest build version. This will also require your Hosts to restart and this may be a good thing as the Management Agents will restart.
If the problem still persists, you may run a diagnostics on your Dell.
I hope this helps.
VCP6-DCV, VCP5, CCNA, MCTS 2008R2, MCSA 2008R2, CCA, ITIL.
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