Block generated a fatal error in a branch that I just upgraded to 1.7.0
"Fatal error: Class 'Icon' not found in /home/bygeorge/public_html/fallout/mod/block/class/Block_Item.php on line 165"
I fixed it by inserting the following line at the head of the file. However, I'm not sure if this is how you want classes to be loaded.
require_once '/home/bygeorge/public_html/fallout/core/class/Icon.php';