If you have a look at the following page on your site, you can see that comments are enabled for that Post...
If they aren't appearing on other Posts, then make sure that you have "Allow comments" and "Allow trackbacks and pingbacks on this page" both ticked, in the Discussion panel for the Post. If you can't see the "Discussion" panel (below the main editor), click on the "Screen Options" tab in the top right corner of your Post and make sure that "Discussion" is selected, so that it appears.
Also, just to clarify, the comment form will only appear on Posts, not Pages. So it wont appear on the Page that you're currently using for your homepage.
Hope this helps.