diff --git a/extensions/fablabchemnitz/flevobezier.py b/extensions/fablabchemnitz/flevobezier.py
index 6c013b13..8ea87284 100644
--- a/extensions/fablabchemnitz/flevobezier.py
+++ b/extensions/fablabchemnitz/flevobezier.py
@@ -65,7 +65,11 @@ def flevobezier(points, z):
         window = points[trail:lead + 1] # Extend the window one more node
         v = window[-3] - window[-2]
         w = window[-1] - window[-2]
-        if dotp(v, w) / dist(v) / dist(w) >= 0.5: # 60 degrees or less, over by angle
+        try:
+            v_w = dist(v) / dist(w)
+        except ZeroDivisionError as e:
+            pout("Division by zero. Check if your path contains duplicate handles.")
+        if dotp(v, w) / v_w >= 0.5: # 60 degrees or less, over by angle
             if maybeover: # backup
                 newcurve = stress(points[prevtrail:lead])[0]
                 res[-3:] = newcurve[1:] # replace the last three nodes in res with those of newcurve