cgi error

hi
I have a little function to use ftputil module to get a file from a
server

def getfile(filename):
import ftputil
host = ftputil.FTPHost(svr, usr,pswd)
host.chdir("/somewhere")
try:
host.download(filename,filename,"a")
except ftputil.FTPError,v:
print v

It works fine when i run it in python , but it won't run when i run my
cgi script
It says AttributeError: 'module' object has no attribute 'FTPHost'
what could be a possible cause? thanks.

.