Index: trunk/autoquest-plugin-core/src/main/java/de/ugoe/cs/autoquest/plugin/PluginLoader.java
===================================================================
--- trunk/autoquest-plugin-core/src/main/java/de/ugoe/cs/autoquest/plugin/PluginLoader.java	(revision 2230)
+++ trunk/autoquest-plugin-core/src/main/java/de/ugoe/cs/autoquest/plugin/PluginLoader.java	(revision 2232)
@@ -97,31 +97,33 @@
 		});
 
-		for (File jarFile : jarFiles) {
-			updateClassLoader(jarFile);
-
-			String pluginName = jarFile.getName().split("-")[2];
-			String pluginClassName = "de.ugoe.cs.autoquest.plugin." + pluginName
-					+ "." + pluginName.toUpperCase() + "Plugin";
-
-			Class<?> pluginClass = null;
-			try {
-				pluginClass = Class.forName(pluginClassName);
-			} catch (ClassNotFoundException e) {
-				throw new PluginLoaderException("No class '" + pluginClassName
-						+ "' found in " + pluginDir + "/" + jarFile.getName());
-			}
-			try {
-				AutoQUESTPlugin pluginObject = (AutoQUESTPlugin) pluginClass
-						.newInstance();
-				plugins.add(pluginObject);
-			} catch (InstantiationException e) {
-				throw new PluginLoaderException("Could not instantiate "
-						+ pluginClassName);
-			} catch (IllegalAccessException e) {
-				throw new PluginLoaderException("Could not access "
-						+ pluginClassName);
-			} catch (ClassCastException e) {
-				throw new PluginLoaderException("Class " + pluginClassName
-						+ " not instance of AutoQUESTPlugin");
+		if (jarFiles != null) {
+			for (File jarFile : jarFiles) {
+				updateClassLoader(jarFile);
+
+				String pluginName = jarFile.getName().split("-")[2];
+				String pluginClassName = "de.ugoe.cs.autoquest.plugin." + pluginName
+						+ "." + pluginName.toUpperCase() + "Plugin";
+
+				Class<?> pluginClass = null;
+				try {
+					pluginClass = Class.forName(pluginClassName);
+				} catch (ClassNotFoundException e) {
+					throw new PluginLoaderException("No class '" + pluginClassName
+							+ "' found in " + pluginDir + "/" + jarFile.getName());
+				}
+				try {
+					AutoQUESTPlugin pluginObject = (AutoQUESTPlugin) pluginClass
+							.newInstance();
+					plugins.add(pluginObject);
+				} catch (InstantiationException e) {
+					throw new PluginLoaderException("Could not instantiate "
+							+ pluginClassName);
+				} catch (IllegalAccessException e) {
+					throw new PluginLoaderException("Could not access "
+							+ pluginClassName);
+				} catch (ClassCastException e) {
+					throw new PluginLoaderException("Class " + pluginClassName
+							+ " not instance of AutoQUESTPlugin");
+				}
 			}
 		}