diff --git a/dedrm_src/kindlekey.py b/dedrm_src/kindlekey.py
index ec0adde..7e02b6c 100644
--- a/dedrm_src/kindlekey.py
+++ b/dedrm_src/kindlekey.py
@@ -40,6 +40,12 @@ from struct import pack, unpack, unpack_from
 import json
 import getopt
 
+try:
+    RegError
+except NameError:
+    class RegError(Exception):
+        pass
+
 # Routines common to Mac and PC
 
 # Wrap a stream so that output gets flushed immediately