It seems you have downloaded or saved the package file in such a way that it has HTML text in it.

If you download the file in the following way it should load without errors:

1. Go to the page of the file you want to download from GitHub.
2. Click it to view the contents within the GitHub UI.
3. In the top right, right click the Raw button.
4. From the browser File menu use "Save as..." and save as "*.m"

You might find this discussion helpful:

http://stackoverflow.com/questions/4604663/github-download-single-files

(I am sorry for this very delayed reply. I saw this post by accident...)