diff --git a/SparkleLib/SparkleConfig.cs b/SparkleLib/SparkleConfig.cs
index 6cbcc3f8..0365a8c5 100755
--- a/SparkleLib/SparkleConfig.cs
+++ b/SparkleLib/SparkleConfig.cs
@@ -277,8 +277,13 @@ namespace SparkleLib {
 
         public bool IdentifierExists (string identifier)
         {
+            if (identifier == null)
+                throw new ArgumentNullException ();
+
             foreach (XmlNode node_folder in SelectNodes ("/sparkleshare/folder")) {
-                if (node_folder ["identifier"].InnerText.Equals (identifier))
+                XmlElement folder_id = node_folder ["identifier"];
+
+                if (folder_id != null && identifier.Equals (folder_id.InnerText))
                     return true;
             }
 
diff --git a/SparkleShare/Windows/SparkleEventLog.cs b/SparkleShare/Windows/SparkleEventLog.cs
index 727dae6b..eefa976f 100644
--- a/SparkleShare/Windows/SparkleEventLog.cs
+++ b/SparkleShare/Windows/SparkleEventLog.cs
@@ -178,7 +178,7 @@ namespace SparkleShare {
                 });
             };
             
-            Controller.UpdateChooserEvent += delegate (SparkleFolder [] folders) {
+            Controller.UpdateChooserEvent += delegate (string [] folders) {
                 Dispatcher.BeginInvoke ((Action) delegate {
                     UpdateChooser (folders);
                 });