I am using SER (last version from CVS ) +SEMS (last version from cvs) with IVR functionality. Python version 2.3

record message
Traceback (most recent call last):
File "/usr/local/etc/ivr/ivr.py", line 65, in ?
if os.path.isdir(messages_path + callee) != True:
TypeError: cannot concatenate 'str' and 'NoneType' objects
(20842) ERROR: run (IvrPython.cpp:968): IVR PYTHON Error: Failed to run "/usr/local/etc/ivr/ivr.py"
(20842) DEBUG: run (IvrPython.cpp:1008): IVR: run finished. stopping rtp stream...

and becouse i dont have any fogest idea about python i am not sure what to do and come here to ask for help