The error that results is the following:
The text reads: [FileDialog_UserInitiated] Arguments:
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=4.1.10111.0& File=System.Windows.dll&Key=FileDialog_UserInitiated
However, when browsing to the URL, you’ll notice that the link no longer exists.
I don’t use Silverlight much and so I haven’t come across this before. Hopefully this helps someone in the future.