Index: trunk/quest-plugin-core/src/main/java/de/ugoe/cs/quest/plugin/PluginLoader.java
===================================================================
--- trunk/quest-plugin-core/src/main/java/de/ugoe/cs/quest/plugin/PluginLoader.java	(revision 757)
+++ trunk/quest-plugin-core/src/main/java/de/ugoe/cs/quest/plugin/PluginLoader.java	(revision 766)
@@ -11,5 +11,4 @@
 import java.net.URL;
 import java.net.URLClassLoader;
-import java.security.InvalidParameterException;
 import java.util.Collection;
 import java.util.Collections;
@@ -52,13 +51,13 @@
 	 *            handle of the directory; in case the handle is
 	 *            <code>null</code> or does not describe a directory, an
-	 *            {@link InvalidParameterException} is thrown
+	 *            {@link IllegalArgumentException} is thrown
 	 */
 	public PluginLoader(File pluginDir) {
 		if (pluginDir == null) {
-			throw new InvalidParameterException(
+			throw new IllegalArgumentException(
 					"Parameter pluginDir must not be null!");
 		}
 		if (!pluginDir.isDirectory()) {
-			throw new InvalidParameterException("File " + pluginDir.getPath()
+			throw new IllegalArgumentException("File " + pluginDir.getPath()
 					+ " is not a directory");
 		}