CGI & Python (error)

[Mix]

When accessing  the  script I get the error:

File "getdate2.py", line 12, in ?
    day=form["day"].value
  File "/usr/lib/python1.5/cgi.py", line 907, in __getitem__
    raise KeyError, key
KeyError: day

The script works from the command line.

My problems is:  the script I am trying to run is based on another one.
This
other script works. I can't  figure out the what is causing the problem
as
the 2 scripts are identical  in every aspect execpt for 1 variable. Both
scripts
are run in a page which has all the required parameters passed to it.
Help. Please...

I hope I'm understandable!