I have an issue with gh-pages of github. The html pages which start with _ ( underscore ) shows the error.
Page does not exist! Read the Full Documentation
I
As of December 27, 2009, you can completely opt-out of Jekyll processing by creating a file named .nojekyll in the root of your pages repo and pushing that to GitHub. This should only be necessary if your site uses directories that begin with an underscore, as Jekyll sees these as special dirs and does not copy them to the final destination.
https://github.com/blog/572-bypassing-jekyll-on-github-pages