When doing a clean install of Moodle 1.8 stable the links in the "Report" column on the environment check page take the form http://localhost/en/admin/environment/unicode which should be http://docs.moodle.org/en/admin/environment/unicode etc.

This is because at that early stage of installation the variable $CFG->docroot is not set. A possible fix would be to add the lines
if (empty($CFG->docroot)) {
$CFG->docroot = 'http://docs.moodle.org';
}
near the start of doc_link() in weblib.php