diff --git a/optimizeimages.py b/optimizeimages.py
index 6fe8b78..b3daff7 100644
--- a/optimizeimages.py
+++ b/optimizeimages.py
@@ -23,11 +23,14 @@ advdef = "advdef"
 
 def check_programs(level):
     path = os.environ.get("PATH").split(os.pathsep)
-
+    
+    def exists_in_path(prog):
+        result = filter(lambda x: os.path.exists(os.path.join(x, prog)), path)
+        return len(result) != 0
+    
     for prog,l in [(pngcrush,1), (optipng,2), (advdef,2)]:
         if l <= level:
-            result = filter(lambda x: os.path.exists(os.path.join(x, prog)), path)
-            if len(result) == 0:
+            if (not exists_in_path(prog)) or (not exists_in_path(prog + ".exe")):
                 raise Exception("Optimization prog %s for level %d not found!" % (prog, l))
 
 def optimize_image(imgpath, imgformat, optimizeimg):
diff --git a/web_assets/functions.js b/web_assets/functions.js
index 0ec7eae..65a78d4 100644
--- a/web_assets/functions.js
+++ b/web_assets/functions.js
@@ -160,7 +160,12 @@ function initMarkers() {
     if (markersInit) { return; }
 
     markersInit = true;
-
+    
+    // first, give all collections an empty array to work with
+    for (i in signGroups) {
+        markerCollection[signGroups[i].label] = [];
+    }
+    
     for (i in markerData) {
         var item = markerData[i];
 
@@ -202,11 +207,8 @@ function initMarkers() {
                         icon: iconURL,
                         visible: false
                         });
-                if (markerCollection[label]) {
-                    markerCollection[label].push(marker);
-                } else {
-                    markerCollection[label] = [marker];
-                }
+                
+                markerCollection[label].push(marker);
 
                 if (item.type == 'sign') {
                     prepareSignMarker(marker, item);