When enabling the auto index on WAMP you will need to make a small cahnge to the apache: httpd-autoindex.conf
This can be found (apending on your version) here: c:\wamp\bin\apache\Apache2.2.17\conf\extra\httpd-autoindex.conf
Alias /icons/ "/apache/icons/"
Replace: "/apache/icons/" with the absolute path to your Apache Icons directory. E.g: C:/wamp/bin/apache/Apache2.2.21/icons/
You need to make sure that you use FORWARD SLASH not BACK SLASH if you are copy/paste from windows.