diff -uNr simias.orig/src/core/CollectionStore/Store.cs simias/src/core/CollectionStore/Store.cs
--- simias.orig/src/core/CollectionStore/Store.cs	2009-02-27 20:32:48.481455316 +0100
+++ simias/src/core/CollectionStore/Store.cs	2009-02-27 20:33:49.312451704 +0100
@@ -528,7 +528,7 @@
 					        Simias.Configuration config = Store.Config;
 					        string raPath = config.Get( "Server", "RAPath" );
 
-					        if (raPath != String.Empty && raPath != "")
+					        if (raPath != String.Empty && raPath != "" && raPath != null)
 						{
 					                string[] racertFiles = Directory.GetFiles( raPath, "*.?er" );
 							foreach ( string file in racertFiles )