Backing Project Doesnt work

The "Back this project" doesnt work.
Im using default settings on Fundraising.

Here its the step-by-step:
1. go to Project page
2. select the amount to donate
3. Press "back this project"

What happens next:

- Loads a "comment page" showing just the ammount options and no button to back the project or anything else. (just a leave your comment bellow the comment area)