Please describe the problem:
Using the command line option --set-volume=xx to set the volume does not work - it fails with an Unhandled Exception, as pasted below. 

Steps to reproduce:
1. Open Banshee and play a song. 
2. Open a terminal and issue the command: banshee --set-volume=50


Actual results:
The following is returned: 
gdi2k@phenom:~$ banshee --set-volume=50

Unhandled Exception: System.ArgumentNullException: Cannot handle a null message; maybe the bus was disconnected
Parameter name: msg
  at NDesk.DBus.Connection.HandleMessage (NDesk.DBus.Message msg) [0x00000] 
  at NDesk.DBus.PendingCall.get_Reply () [0x00000] 
  at NDesk.DBus.Connection.SendWithReplyAndBlock (NDesk.DBus.Message msg) [0x00000] 
  at NDesk.DBus.BusObject.SendMethodCall (System.String iface, System.String member, System.String inSigStr, NDesk.DBus.MessageWriter writer, System.Type retType, System.Exception& exception) [0x00000] 
  at IPlayerEngineServiceProxy.set_Volume (UInt16 ) [0x00000] 
  at Halie.Client.HandlePlayerCommands () [0x00000] 
  at Halie.Client.Main () [0x00000] 
  at (wrapper managed-to-native) System.AppDomain:ExecuteAssembly (System.Reflection.Assembly,string[])
  at System.AppDomain.ExecuteAssemblyInternal (System.Reflection.Assembly a, System.String[] args) [0x00000] 
  at System.AppDomain.ExecuteAssembly (System.String assemblyFile, System.Security.Policy.Evidence assemblySecurity, System.String[] args) [0x00000] 
  at (wrapper remoting-invoke-with-check) System.AppDomain:ExecuteAssembly (string,System.Security.Policy.Evidence,string[])
  at System.AppDomain.ExecuteAssembly (System.String assemblyFile) [0x00000] 
  at (wrapper remoting-invoke-with-check) System.AppDomain:ExecuteAssembly (string)
  at Booter.Booter.BootClient (System.String clientName) [0x00000] 
  at Booter.Booter.Main () [0x00000] 

Expected results:
Volume is set to 50%.

Does this happen every time?
Yes

Other information: