diff --git a/nodes/textures/imagemap.py b/nodes/textures/imagemap.py
index b2f31626..de7e2943 100644
--- a/nodes/textures/imagemap.py
+++ b/nodes/textures/imagemap.py
@@ -66,11 +66,13 @@ def update_image(self, context):
                               description="Brightness multiplier")
 
     def update_is_normal_map(self, context):
-        color_output = self.outputs["Color"]
-        bump_output = self.outputs["Bump"]
-        alpha_output = self.outputs["Alpha"]
+        id = self.outputs.find("Color")
+        color_output = self.outputs[id]
+        id = self.outputs.find("Bump")
+        bump_output = self.outputs[id]
+        id = self.outputs.find("Alpha")
+        alpha_output = self.outputs[id]
         was_color_enabled = color_output.enabled
-
         color_output.enabled = not self.is_normal_map
         alpha_output.enabled = not self.is_normal_map
         bump_output.enabled = self.is_normal_map