Relative path wont work?

Hey I have this file called LoadfileWB.au3 its location is:

C:\Documents and Settings\User\Desktop\KSM-500\kWorkbench\LoadFilekWB.au3

Inside this file is this path

#include-once
#include <C:\Documents and Settings\User\Desktop\Library\Error_log.au3>

The second include statement. I want it to be a relative path so I can run it in my virtual box.

However I have tried the following below and still cant get it to work.

#include <...\Library\Error_log.au3>
#include <..\Library\Error_log.au3>
#include <.\Library\Error_log.au3>