Error on when try to enable ftp

I recevie the following error whenever I try to enable and save ftp setting. I have OMV running on a raspberry pi, what am I doing wrong or missing here?
Error
#4000: exception 'OMVException' with message 'Failed to execute command 'export
LANG=C; invoke-rc.d 'proftpd' start 2>&1': Starting ftp server:
proftpdraspberrypi proftpd[11297]: mod_tls_memcache/0.1: notice: unable to
register 'memcache' SSL session cache: Memcache support not enabled Illegal
instruction failed! invoke-rc.d: initscript proftpd, action "start" failed.' in
/usr/share/php/openmediavault/initscript.inc:176 Stack trace: #0
/usr/share/php/openmediavault/initscript.inc(141):
OMVSysVInitScript->invoke('start') #1
/usr/share/php/openmediavault/initscript.inc(61): OMVSysVInitScript->start()
#2 /usr/share/openmediavault/engined/module/proftpd.inc(86):
OMVSysVInitScript->exec() #3
/usr/share/openmediavault/engined/rpc/config.inc(206):
OMVModuleProftpd->startService() #4 [internal function]:
OMVRpcServiceConfig->applyChanges(Array, Array) #5
/usr/share/php/openmediavault/rpcservice.inc(125): call_user_func_array(Array,
Array) #6 /usr/share/php/openmediavault/rpcservice.inc(158):
OMVRpcServiceAbstract->callMethod('applyChanges', Array, Array) #7
/usr/share/openmediavault/engined/rpc/config.inc(224):
OMVRpcServiceAbstract->callMethodBg('applyChanges', Array, Array) #8
[internal function]: OMVRpcServiceConfig->applyChangesBg(Array, Array) #9
/usr/share/php/openmediavault/rpcservice.inc(125): call_user_func_array(Array,
Array) #10 /usr/share/php/openmediavault/rpc.inc(79):
OMVRpcServiceAbstract->callMethod('applyChangesBg', Array, Array) #11
/usr/sbin/omv-engined(501): OMVRpc::exec('Config', 'applyChangesBg', Array,
Array, 1) #12 {main}

I Comment line with # and still have same error.