Yeoman is great, but it do not include the twitter bootstrap icons by default.
I have figured out a work around for the issue. Hope yeoman will fix it in future.
First download the bootstrap image and place in inside app/images folder
Search for compass task. It should lok something like this:
sassDir: '<%= yeoman.app %>/styles',
imagesDir: '<%= yeoman.app %>/images',
imagesDir: 'images' after
debugInfo: true . It should like below :
Note that it will remove the error message but the images will appear now.