Running 'grunt' produce the following errors

[vsymguysung]

Running "clean:build" (clean) task
Cleaning "tmp"...OK

Running "copy:stage" (copy) task
Created 3 directories, copied 9 files

Running "lock" task

Running "concurrent:debug" (concurrent) task
Running "copy:prepare" (copy) task
Running "emberTemplates:debug" (emberTemplates) task
File "tmp/public/assets/templates.js" created.

Done, without errors.

Running "less:compile" (less) task

FileError: '../../vendor/bootstrap/less/variables.less' wasn't found in app/styles/bootstrap.less on line 12, column 1:
11 // Core variables and mixins
12 @import "../../vendor/bootstrap/less/variables.less";
13 @icon-font-path: "./fonts/";
Warning: Error compiling app/styles/bootstrap.less Use --force to continue.

Aborted due to warnings.
Warning: Use --force to continue.

    Aborted due to warnings.

[vsymguysung]

Running "bower install" resolved the issue above.