Please navigate to your page admin, click Screen Options in the top right corner:
…and check Discussion and Comments boxes. Then scroll down to Discussion section and check the Allow comments option. This should enable comment box on your page.
Also, make sure that you comments are allowed from WP admin > Settings > Discussion
I have tested comments on my end, and they are working just fine http://screencast.com/t/XNfKuAHNIf
If this is still no-go after that, you can try to disable all additional plugins because of possible plugin conflict.
All the Best!