Alors, ça donne ça :)
Unhandled Exception:
System.ObjectDisposedException: Cannot access a closed Stream.
at (wrapper managed-to-native) System.Object.icall_wrapper_mono_delegate_end_invoke(object,intptr)
at (wrapper delegate-end-invoke) <Module>.end_invoke_void__thisIAsyncResult(System.IAsyncResult)
at System.Media.SoundPlayer.AsyncFinished (System.IAsyncResult ar) [0x0000c] in <a9a08e39ba304bd0a84c49bd158dfc02>:0
at (wrapper managed-to-native) System.Runtime.Remoting.Messaging.AsyncResult.Invoke(System.Runtime.Remoting.Messaging.AsyncResult)
at System.Runtime.Remoting.Messaging.AsyncResult.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () [0x00000] in <d0e12f672b88444ab4b6d9b2ecf20142>:0
at System.Threading.ThreadPoolWorkQueue.Dispatch () [0x00096] in <d0e12f672b88444ab4b6d9b2ecf20142>:0
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback () [0x00000] in <d0e12f672b88444ab4b6d9b2ecf20142>:0
[ERROR] FATAL UNHANDLED EXCEPTION: System.ObjectDisposedException: Cannot access a closed Stream.
at (wrapper managed-to-native) System.Object.__icall_wrapper_mono_delegate_end_invoke(object,intptr)
at (wrapper delegate-end-invoke) <Module>.end_invoke_voidthisIAsyncResult(System.IAsyncResult)
at System.Media.SoundPlayer.AsyncFinished (System.IAsyncResult ar) [0x0000c] in <a9a08e39ba304bd0a84c49bd158dfc02>:0
at (wrapper managed-to-native) System.Runtime.Remoting.Messaging.AsyncResult.Invoke(System.Runtime.Remoting.Messaging.AsyncResult)
at System.Runtime.Remoting.Messaging.AsyncResult.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem () [0x00000] in <d0e12f672b88444ab4b6d9b2ecf20142>:0
at System.Threading.ThreadPoolWorkQueue.Dispatch () [0x00096] in <d0e12f672b88444ab4b6d9b2ecf20142>:0
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback () [0x00000] in <d0e12f672b88444ab4b6d9b2ecf20142>:0