fixed Ajax errors not being displayed in the UI.

NzbDrone.Common/Exceptions/NzbDroneException.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NzbDrone.Common.Exceptions
+{
+
+
+    public abstract class NzbDroneException : ApplicationException
+    {
+        protected NzbDroneException(string message, params object[] args)
+            : base(string.Format(message, args))
+        {
+
+        }
+
+
+        protected NzbDroneException(string message)
+            : base(message)
+        {
+
+        }
+    }
+
+}