Apple Has Blocked free USER From Updating to iOS Beta Firmware

Apple has blocked the ability to update to iOS beta firmware without having your device registered on a developer account.

With previous builds of iOS 7, non-developers could install the betas as long as they chose 'UPDATE' instead of 'RESTORE' when installing the firmware.

Performing an update on an unregistered device will now install the firmware but will attempt to activate before loading for the first time. The following error is then presented...

Activation Error:

This device is not registered as part of the iPhone Developer Program. If you are a member of the iPhone Developer Program, please register your device in the iPhone Developer Program Portal at  http://developer.apple.com/iphone.

Thus if you are not a developer, please don't try to update to beta 2. Also, since the betas expire, we recommend you restore to iOS 7.0.4.

Source : iClarified