problem with specifying directory when using file_get_content()

[hanhao]

problem with specifying directory when using file_get_content()

i got a problem with this function
sim.txt is the file that i wish to read. it is stored in website_root\color_scripts\sim.txt

this is my code

$simtxt_contents = file_get_contents("color_scripts\sim.txt");

here is the error message

Warning: file_get_contents(color_scripts\sim.txt) [function.file-get-contents]: failed to open stream: No such file or directory in C:\Program Files\xampp\htdocs\website_root\test_colorsim.php on line 21

the strange thing is i specified the directory as "color_scripts\sim.txt" , and NOT \test_colorsim.php\

is there anyway to solve this problem?
do i need to escape ta directory up?
using apache on my computer
please help

[hanhao]

i managed to solve my problem
here is the solution

$server_root = $_SERVER['DOCUMENT_ROOT'];
$simtxt_contents = file_get_contents("$server_root/website_root/color_scripts/sim.txt");