diff --git a/chdkptp/__init__.py b/chdkptp/__init__.py
index c8b64a7..ddcf6f0 100644
--- a/chdkptp/__init__.py
+++ b/chdkptp/__init__.py
@@ -1,4 +1,5 @@
 from chdkptp.device import ChdkDevice, list_devices, DeviceInfo
+from chdkptp.lua import PTPError
 
 __version__ = "0.1.3"
-__all__ = ['ChdkDevice', 'list_devices', 'DeviceInfo']
+__all__ = ['ChdkDevice', 'list_devices', 'DeviceInfo', 'PTPError']
diff --git a/chdkptp/lua.py b/chdkptp/lua.py
index 370f04b..28cac75 100644
--- a/chdkptp/lua.py
+++ b/chdkptp/lua.py
@@ -11,13 +11,13 @@
 
 class PTPError(Exception):
     def __init__(self, err_table):
-        msg = err_table.get('message')
-        errcode = err_table.get('ptp_rc')
+        msg = err_table['msg']
+        errcode = err_table['ptp_rc']
         super(PTPError, self).__init__(
             "{0} (ptp_code: {1})".format(msg or "Unknown error",
                                          errcode or 'unknown'))
         self.ptp_code = errcode
-        self.traceback = err_table.get('traceback')
+        self.traceback = err_table['traceback']
 
 
 class LuaContext(object):