Have replied to your issue on github itself. My guess is the problem was due to the package name containing spaces. Have made a commit which should hopefully address that. So if you update master branch and try again, it should be fine.
From a fork you wouldn’t want to run “grunt publish”. That command tries to update the live gitbook as in the examples project gitbook from it’s gh-pages branch. If you’re making content updates on a fork, please just submit a pull request to master branch on the source repo. If you want to test the changes you made locally, from the GitBook editor tool you have the option to “Preview Website” from it’s menu’s or you can just run “grunt” from the gitbook_src folder which should build the site locally that you can check with a browser. I’ve added a note to the Update Instructions wiki indicating the same.