This is a global issue and I am very surprised that do not get any solution on internet.
When we create a site using Project Tracking Workspace template (Fantastic 40), following ICON images are missing from the site
It shows red cross icon instead of following icons.
Site Feature Icon:
Download missing icons from internet and add them into images folder on server
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\TEMPLATE\IMAGES folder
After which list and feature looks like