C# WPF toolkit DataGrid and DataSet

Question

Hi.  I'm using C# (net 3.5) and I'm trying to get the data from a DataSet object to display in the WPF toolkit's DataGrid control but I'm not having any luck.
The MSDN says I just need to set the DataContext to my DataSet.Table but that's not working.  Anyone know what I'm doing wrong?
 
Thanks,
  Sam.