Cannot setup local mirror (avast4)

I use this servers definitions file,

[servers]
count=1

[server0]
name=My Server
url=http://localhost/avast

The error is:
Server definition file for ‘main’ (D:\Program Files\Alwil Software\Avast4\Setup\servers.def) is invalid.

How to fix this error?
May be this is becouse there is no signature in this file?

Exactly, you must not change servers.def file.

How to tell Avast to load updates from my server ?

I made local mirror using perl scripts dowloaded from Avast! web site.

In iAVS documentation I read the following: (p. 4.1. How to mirror):

… create the following files:
servers.def with settings of our servers