Please describe the problem:
When plugging in a device with the .is_audio_player file present, Banshee throws up an exception to do with HAL:


[Warn  20:57:24.722] Caught an exception - Object reference not set to an instance of an object (in `Banshee.Dap.MassStorage')
  at Banshee.Dap.MassStorage.MassStorageSource.get_MediaCapabilities () [0x00000] in /var/abs/local/yaourtbuild/banshee-1-svn/src/banshee/src/Dap/Banshee.Dap.MassStorage/Banshee.Dap.MassStorage/MassStorageSource.cs:103
  at Banshee.Dap.DapSource.Initialize () [0x0010a] in /var/abs/local/yaourtbuild/banshee-1-svn/src/banshee/src/Dap/Banshee.Dap/Banshee.Dap/DapSource.cs:114
  at Banshee.Dap.MassStorage.MassStorageSource.DeviceInitialize (IDevice device) [0x00057] in /var/abs/local/yaourtbuild/banshee-1-svn/src/banshee/src/Dap/Banshee.Dap.MassStorage/Banshee.Dap.MassStorage/MassStorageSource.cs:69
  at Banshee.Dap.DapService.FindDeviceSource (IDevice device) [0x00025] in /var/abs/local/yaourtbuild/banshee-1-svn/src/banshee/src/Dap/Banshee.Dap/Banshee.Dap/DapService.cs:127 

Steps to reproduce:
1. Start Banshee
2. Plug in phone, and select file transfer mode.
3. Memory stick shows up on desktop.
4. No response in Banshee's window, but exception shown in command line output.


Actual results:
Banshee throws up a HAL exception

Expected results:
Banshee displays the Mtp device and allows me to add/remove files from it.

Does this happen every time?
Yes

Other information:
Distro: ArchLinux
Bug doesn't happen with Banshee 0.98.3.
Disabling and re-enabling the mtp plugin results in the exception being thrown again.