Can't run update

Failed to execute command 'export LANG=C; apt-get update 2>&1': E: Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable) E: Unable to lock directory /var/lib/apt/lists/


Fehler #4000:
exception 'OMVException' with message 'Failed to execute command 'export LANG=C; apt-get update 2>&1': E: Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable)
E: Unable to lock directory /var/lib/apt/lists/' in /usr/share/openmediavault/engined/rpc/apt.inc:276
Stack trace:
#0 [internal function]: OMVRpcServiceApt->update(NULL, Array)
#1 /usr/share/php/openmediavault/rpcservice.inc(125): call_user_func_array(Array, Array)
#2 /usr/share/php/openmediavault/rpc.inc(79): OMVRpcServiceAbstract->callMethod('update', NULL, Array)
#3 /usr/sbin/omv-engined(500): OMVRpc::exec('Apt', 'update', NULL, Array, 1)
#4 {main}