Notice: Undefined index: src in theme_admin_menu_icon()
ISSUE : Notice: Undefined index: src in theme_admin_menu_icon() (line 924 of /path/to/drupal/sites/all/modules/contrib/admin_menu/admin_menu.inc).
SOLUTION : This may be caused when you recently update the admin module. You can solve it by going into the database and flush all the "cache" tables like cache blocks, cache_theme etc. just select all the tables with preceding "cache_" name and empty them from phpmyadmin. This will solve your problem