APPDATA is not returned in Python executed via CGI
%APPDATA% is a special variable that expands to the "Application Data" directory of the user who expands the variable (i.e., who runs a script). Apache is not running as you, so it has no business knowing about your APPDATA directory. 
You should either hard-code the relevant path into your script, or replace it with a path relative to the location of the script, e.g., r'..\data\nltk_data'. If you really need to, you can recover the absolute location of your script by looking at __file__.
I'm using Python with the NLTK toolkit in Apache via CGI. The toolkit need to know the APPDATA directory, but when executed in the server, the os.environ not lists theAPPDATA.
When I execute a simple print os.envrion in console, APPDATA is present, but not when executed via CGI in the web server.
What is going on? How can I solve this? I'm new to Python and I'm just learning it yet.