help?

[Hialls]

if (file_exists('./install/install.php') == true)
{
print_stop_message('security_alert_x_still_exists' , 'install.php');
}
is taken from .admincp/global.php i want to use a similar script however im unable to use file_exists due to my server settings

If you use open_basedir in php.ini and use file_exists for file outside open_basedir path, you will not be warned at log and file_exists returns false even if file really exists. -- quote from php.net

Im wondering if anyone could tell me a different method?
All i can think of is filesize() but when the file doesn't exist with this it throws an error at the user.