Index: trunk/autoquest-plugin-mfc/src/main/java/de/ugoe/cs/autoquest/plugin/mfc/LogPreprocessor.java
===================================================================
--- trunk/autoquest-plugin-mfc/src/main/java/de/ugoe/cs/autoquest/plugin/mfc/LogPreprocessor.java	(revision 2215)
+++ trunk/autoquest-plugin-mfc/src/main/java/de/ugoe/cs/autoquest/plugin/mfc/LogPreprocessor.java	(revision 2233)
@@ -144,9 +144,13 @@
 		}
 		String absolutPath = folder.getAbsolutePath();
-		for (String filename : folder.list()) {
-			String source = absolutPath + "/" + filename;
-			Console.traceln(Level.INFO, "Processing file: " + source);
-			processFile(source, targetFile);
-		}
+		
+		String[] filenames = folder.list();
+		if (filenames != null) {
+			for (String filename : filenames) {
+				String source = absolutPath + "/" + filename;
+				Console.traceln(Level.INFO, "Processing file: " + source);
+				processFile(source, targetFile);
+			}
+	    }
 
 		if (sessionOpen) {