failed connecting esx4 host to vcenter

Need of your help.

i have a 3hosts cluster. 1 host was acting funny and connection with vI client fails.i dissconnected it from the Vcenter and now reconnecting it fails. it comes back with request timeout.

vmware-cmd -l

returns-- vim.fault.HostConnectFault: Failed to acquire session manager while querying for local ticket. ((8, 'EOF occurred in violation of protocol'))

i've tried restarting the management service, but it doesn't help.

need ur advice urgently, cos i hv lots of productioin vms on the host.