In the config-dist.php file there is this:
//=========================================================================
// 5. DIRECTORY LOCATION (most people can just ignore this setting)
//=========================================================================
// A very few webhosts use /admin as a special URL for you to access a
// control panel or something. Unfortunately this conflicts with the
// standard location for the Moodle admin pages. You can work around this
// by renaming the admin directory in your installation, and putting that
// new name here. eg "moodleadmin". This should fix all admin links in Moodle.
// After any change you need to visit your new admin directory
// and purge all caches.
$CFG->admin = 'admin';
Wonder if that's the issue ... add the above $CFG line to your config.php file.
Also, are there any .htaccess files?
'spirit of sharing', Ken