"Start campaign" button doesn't do anything

On a group page (e.g. https://go.vumi.org/contacts/group/c7de0a0dfdc6423cb16c50a12c0529d6/)
There is a "start campaign" button in the header (see screenshot)
* Click on the "start campaign" button 
* a popup confirmation screen is displayed
* Click the "start campaign" button in the popup
* Nothing happens

Please remove the "start campaign" button from the header till we can figure out the user flow for this action.

![screen shot 2013-08-15 at 12 12 54 pm](https://f.cloud.github.com/assets/1521387/968108/15ac0c5e-0594-11e3-8923-ab6eaa44efae.png)