If Ruby or Rails (too), your backtrack means the error comes from the gem code itself. If you opened these files and followed them, you could see how Sass Gem works.
EDIT. . If you manually installed / installed the gem, it is better to run bundle install so that you correctly meet the specifications in Gemfile.lock . If such a file seems new to you, I highly recommend reading http://bundler.io/ , a gem manager that allows you to control which gems / versions are needed for your application!
NOTE If you work with Rails, the rest of my answer below may help. (From personal experience I had a couple of months ago.)
This error means that you do not have the dumdum.scss file in your directory, most likely app/assets/stylesheets/ . I suggest doing a quick grep search where you use dumdum . For example, in the application I'm working on, I have a _colors.scss file, and it references and redefines the stylesheet (for bootstrapping) as @import "colors"; .
source share