I made the suggestion from surukume but still can't get it to functioning.
I see only red cros and no marker images and get this error:
Warning: opendir(/home/www/findbiblioteket.dk//wp-content/plugins/GoogleMapper/icons) [function.opendir]: failed to open dir: No such file or directory in /home/www/findbiblioteket.dk/blog/wp-content/plugins/GoogleMapper/admin/Icons/form_icon.inc.php on line 41
when I choose "Manage Icons & Marker Types"