Exception 'NoneType' object is not callable

Traceback (most recent call last):
  File "BTSfuncs.py", line 53, in wrapcall
    rslt = func(*args, **kws)
TypeError: 'NoneType' object is not callable
Request:
METHOD = GET
PATH = /BTS/.css
XTRAPATH = 
PROTOCOL = HTTP/1.0
Headers:
 PATH_INFO = '/BTS/.css'
 SERVER_NAME = 'www.equi4.com'
 REMOTE_ADDR = '208.70.28.84'
 GATEWAY_INTERFACE = 'CGI/1.1'
 SERVER_SOFTWARE = 'Apache/1.3.27 (Linux/SuSE) mod_ssl/2.8.12 OpenSSL/0.9.6i mod_python/2.7.10 Python/2.2.2 mod_perl/1.27'
 SCRIPT_NAME = '/BTS.cgi'
 REQUEST_METHOD = 'GET'
 PATH_TRANSLATED = '/home/www/equi4.com/BTS/.css'
 SERVER_PORT = '80'
 SERVER_PROTOCOL = 'HTTP/1.0'
 DOCUMENT_ROOT = '/home/www/equi4.com'
PARAMS: None
QUERY:
  = ''
Buffer: ''