Please describe the problem:
After upgrading from 1.3.2 to 1.3.3, playing any music file from within Banshee fails due to an error in the Player Engine, specifically: Object reference not set to an instance of an object. 

Steps to reproduce:
1. Upgrade to Banshee 1.3.3
2. Start Banshee
3. Attempt to play a song from your music collection.


Actual results:
Banshee is unable to play the song and throws an error.

Expected results:
The song plays as expected.

Does this happen every time?
Yes.

Other information:
Attached is the output from 'banshee --debug' with the important parts pasted below:

[Warn  21:58:03.991] Caught an exception - Object reference not set to an instance of an object (in `Banshee.Services')
  at Banshee.MediaEngine.PlayerEngineService.FindSupportingEngine (Banshee.Base.SafeUri uri) [0x00036] in /build/buildd/banshee-1.3.3/src/Core/Banshee.Services/Banshee.MediaEngine/PlayerEngineService.cs:337 
  at Banshee.MediaEngine.PlayerEngineService.OpenCheck (System.Object o) [0x0006b] in /build/buildd/banshee-1.3.3/src/Core/Banshee.Services/Banshee.MediaEngine/PlayerEngineService.cs:306 
  at Banshee.MediaEngine.PlayerEngineService.OpenPlay (Banshee.Collection.TrackInfo track, Boolean play) [0x0001e] in /build/buildd/banshee-1.3.3/src/Core/Banshee.Services/Banshee.MediaEngine/PlayerEngineService.cs:275 
[Error 21:58:03.993] Problem with Player Engine - Object reference not set to an instance of an object
[Debug 21:58:03.998] (libbanshee:player) bp_stop: setting state to GST_STATE_NULL

It should also be noted that Banshee is throwing a lot of exceptions from many different components as well.

Tested on: Ubuntu Intrepid using the Banshee Unstable repos.