Done.  Here's the stacktrace that was in the terminal:

~$ banshee
[Info  21:52:43.959] Running Banshee 2.2.1: [Ubuntu 11.10 (linux-gnu, i686) @ 2011-12-19 14:51:26 UTC]
Full thread dump:

"<unnamed thread>" tid=0x0xb761ab60 this=0x0x56f18 thread handle 0x403 state : not waiting owns ()
  at Mono.Addins.Serialization.BinaryXmlReader.Skip () <0x0000a>
  at Mono.Addins.Serialization.BinaryXmlReader.SkipToValue (string) <0x00063>
  at Mono.Addins.Serialization.BinaryXmlReader.ReadValue (string) <0x00013>
  at Mono.Addins.Database.FileDatabase.ReadObject (string,Mono.Addins.Serialization.BinaryXmlTypeMap) <0x0006b>
  at Mono.Addins.Database.AddinHostIndex.Read (Mono.Addins.Database.FileDatabase,string) <0x0001f>
  at Mono.Addins.Database.AddinDatabase.GetAddinHostIndex () <0x00087>
  at Mono.Addins.Database.AddinDatabase.GetAddinForHostAssembly (string,string) <0x0007f>
  at Mono.Addins.AddinRegistry.GetAddinForHostAssembly (string) <0x0003f>
  at Mono.Addins.AddinEngine.CheckHostAssembly (System.Reflection.Assembly) <0x000c3>
  at Mono.Addins.AddinEngine.ActivateRoots () <0x00043>
  at Mono.Addins.AddinEngine.Initialize (System.Reflection.Assembly,string,string,string) <0x0018f>
  at Mono.Addins.AddinManager.Initialize (string) <0x00043>
  at Banshee.ServiceStack.ServiceManager.InitializeAddins () <0x0003f>
  at Banshee.ServiceStack.ServiceManager.DefaultInitialize () <0x00013>
  at Banshee.ServiceStack.Application.Initialize () <0x0000b>
  at Banshee.Gui.GtkBaseClient.Initialize (bool) <0x0003b>
  at Banshee.Gui.GtkBaseClient..ctor (bool,string) <0x00023>
  at Banshee.Gui.GtkBaseClient..ctor () <0x00017>
  at Nereid.Client..ctor () <0x00013>
  at (wrapper runtime-invoke) object.runtime_invoke_void__this__ (object,intptr,intptr,intptr) <0xffffffff>
  at (wrapper managed-to-native) System.Reflection.MonoCMethod.InternalInvoke (System.Reflection.MonoCMethod,object,object[],System.Exception&) <0xffffffff>
  at System.Reflection.MonoCMethod.Invoke (object,System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo) <0x00197>
  at System.Reflection.MonoCMethod.Invoke (System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo) <0x00024>
  at System.Reflection.ConstructorInfo.Invoke (object[]) <0x00042>
  at System.Activator.CreateInstance (System.Type,bool) <0x001c3>
  at System.Activator.CreateInstance (System.Type) <0x00013>
  at Banshee.Gui.GtkBaseClient.Startup () <0x00017>
  at Hyena.Gui.CleanRoomStartup.Startup (Hyena.Gui.CleanRoomStartup/StartupInvocationHandler) <0x00087>
  at Banshee.Gui.GtkBaseClient.Startup<T> () <0x00073>
  at Banshee.Gui.GtkBaseClient.Startup<T> (string[]) <0x000eb>
  at Nereid.Client.Main (string[]) <0x00017>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void_object (object,intptr,intptr,intptr) <0xffffffff>
  at (wrapper managed-to-native) System.AppDomain.ExecuteAssembly (System.AppDomain,System.Reflection.Assembly,string[]) <0xffffffff>
  at System.AppDomain.ExecuteAssemblyInternal (System.Reflection.Assembly,string[]) <0x0003b>
  at System.AppDomain.ExecuteAssembly (string,System.Security.Policy.Evidence,string[]) <0x00027>
  at (wrapper remoting-invoke-with-check) System.AppDomain.ExecuteAssembly (string,System.Security.Policy.Evidence,string[]) <0xffffffff>
  at System.AppDomain.ExecuteAssembly (string) <0x0001b>
  at (wrapper remoting-invoke-with-check) System.AppDomain.ExecuteAssembly (string) <0xffffffff>
  at Booter.Booter.BootClient (string) <0x0006b>
  at Booter.Booter.Main () <0x001b7>
  at (wrapper runtime-invoke) object.runtime_invoke_void (object,intptr,intptr,intptr) <0xffffffff>