Re-raise the Res.Error if the file doesn't exist.
diff --git a/Mac/Lib/macresource.py b/Mac/Lib/macresource.py
index 4eaf076..23713a5 100644
--- a/Mac/Lib/macresource.py
+++ b/Mac/Lib/macresource.py
@@ -91,6 +91,8 @@
 			# Finally try decoding an AppleSingle file
 			pathname = _decode(pathname)
 			refno = Res.FSOpenResourceFile(pathname, u'', 1)
+		else:
+			raise
 	return refno
 	
 def _decode(pathname):