diff --git a/src/main/java/myutil/FileUtils.java b/src/main/java/myutil/FileUtils.java
index 5a120b797c69a67eeb0dac1cee9ff94167c44e9b..3d3b0f27bbccf18e23af38e9fe1d78f6fa167dbc 100755
--- a/src/main/java/myutil/FileUtils.java
+++ b/src/main/java/myutil/FileUtils.java
@@ -75,12 +75,15 @@ public class FileUtils extends org.apache.commons.io.FileUtils{
 
 
     public static String getExtension(File f) {
+        return getExtension(f.getName());
+    }
+    
+    public static String getExtension(String name) {
         String ext = "";
-        String s = f.getName();
-        int i = s.lastIndexOf('.');
+        int i = name.lastIndexOf('.');
 
-        if (i > 0 &&  i < s.length() - 1) {
-            ext = s.substring(i+1).toLowerCase();
+        if (i > 0 &&  i < name.length() - 1) {
+            ext = name.substring(i+1).toLowerCase();
         }
         return ext;
     }
diff --git a/src/main/java/ui/interactivesimulation/JFrameInteractiveSimulation.java b/src/main/java/ui/interactivesimulation/JFrameInteractiveSimulation.java
index b0163e7142feca335eae7d12bf593bc55498ccc0..3bbcf132a3de8b5da0670eb832fb8b9496eca307 100755
--- a/src/main/java/ui/interactivesimulation/JFrameInteractiveSimulation.java
+++ b/src/main/java/ui/interactivesimulation/JFrameInteractiveSimulation.java
@@ -2487,9 +2487,10 @@ public class JFrameInteractiveSimulation extends JFrame implements ActionListene
 	        	else
 	        		filename = directory + filename;
 	        }
-	        
-	        SpecConfigTTool.ExternalCommand1 = SpecConfigTTool.ExternalCommand1.replace(SpecConfigTTool.lastVCD, filename);
-	        SpecConfigTTool.lastVCD = filename;
+	        if ("vcd".equals(FileUtils.getExtension(filename))) {
+	        	SpecConfigTTool.ExternalCommand1 = SpecConfigTTool.ExternalCommand1.replace(SpecConfigTTool.lastVCD, filename);
+	        	SpecConfigTTool.lastVCD = filename;
+	        }
 
 	        // DB: now useless check
 //	        if (param.length() >0) {
diff --git a/src/main/java/ui/window/JFrameRequirementTable.java b/src/main/java/ui/window/JFrameRequirementTable.java
index f75637f2d339c38f8330324057831d5d8f8d3e4c..5c5a4fd820ccd4bb2b11a4c77e20300aefa72136 100755
--- a/src/main/java/ui/window/JFrameRequirementTable.java
+++ b/src/main/java/ui/window/JFrameRequirementTable.java
@@ -253,9 +253,13 @@ public	class JFrameRequirementTable extends JFrame implements ActionListener /*,
 		String path;
 		if (SpecConfigTTool.DocGenPath.length() > 0) {
 			path = SpecConfigTTool.DocGenPath + "/";
+			File dir = new File(path);
+			if (!dir.exists())
+				dir.mkdirs();
 		} else {
 			path = "";
 		}
+		
 		path += DOC_GEN_NAME;//"tablereq.html";
 		
 		try {