diff --git a/python/tk_houdini_arnold/handler.py b/python/tk_houdini_arnold/handler.py
index cc23fb3..147c742 100644
--- a/python/tk_houdini_arnold/handler.py
+++ b/python/tk_houdini_arnold/handler.py
@@ -114,9 +114,8 @@ def exportASSFile(self, **kwargs):
         # callback when export ass files is selected
 
         node = kwargs["node"]
-        parm = kwargs["parm"]
 
-        self.__updateASSParm(node, parm)
+        self.__updateASSParm(node)
 
     # private functions
 
@@ -295,9 +294,12 @@ def __updateAOVParm(self, node, parm):
             parm_path.set("Disabled")
             parm_path.lock(True)
 
-    def __updateASSParm(self, node, parm):
+    def __updateASSParm(self, node):
         # update ass file location parameter
 
+        # set parm
+        parm = node.parm("ar_ass_export_enable")
+
         # if checkbox is ticked
         if parm.eval():
             node.parm("ar_ass_file").lock(False)