diff --git a/direct/src/dist/FreezeTool.py b/direct/src/dist/FreezeTool.py
index f7b2ea9b91..237deb9cf3 100644
--- a/direct/src/dist/FreezeTool.py
+++ b/direct/src/dist/FreezeTool.py
@@ -1299,7 +1299,8 @@ class Freezer:
         for moduleName, module in list(self.mf.modules.items()):
             if module.__code__:
                 origPathname = module.__code__.co_filename
-                replace_paths.append((origPathname, moduleName))
+                if origPathname:
+                    replace_paths.append((origPathname, moduleName))
         self.mf.replace_paths = replace_paths
 
         # Now that we have built up the replacement mapping, go back