Was using wrong part of class name as property prefix

src/net/java/sip/communicator/service/protocol/ProtocolProviderFactory.java

@@ -520,6 +520,6 @@ private String getFactoryImplPackageName()
     {
         String className = getClass().getName();
 
-        return className.substring(className.lastIndexOf('.'));
+        return className.substring(0, className.lastIndexOf('.'));
     }
 }