Making changes to a python cgi to be put on a network

[lamar_air]

I have a python cgi that i wrote.  The way it works is a user fills
out necessary information on a web form, click submit and the python
script is executed.  The script retrieves variables from the form and
writes them to a txt file.  The script then calls a executable which
uses this txt file as a set of input parameters.

I'm using this to call the executable 
os.system("webtablx4002")
and then i just added webtablx4002 at c:\folder1\folder2 to the
environment variables paths.

I need this executable to be able to run from whatever directory the
form is located in.  So if whoever puts this program on the server it
will all be in one directory and it would be nice not to have to
change the code to be specific to that directory.
Is there code to get a directoy path for the script or for the form,
where it is located when it is run?