Demo install is broken

Hi,
Just purchased this theme and the demo install doesn’t want to work.

I do a clean install of WP 4.0
I install the theme
I then do the option to import the demo install

Wordpress then tells me that the db needs updating
This completes
then when I try to access any admin page it tells me I do not have permission.
I have done nothing else (no plugin installs etc) This has happened twice now.

The site itself can be viewed and it looks like the demo install was fine