I think I killed my site... New Blog template returns a blank page...

I installed the new blog template - to help speed up blog creation... however, when adding a new blog, and clicking submit I land on a blank page... So I removed the plugin, and I still land on the blank page:

This is the url I get..

http://example.comewp-admin/network/site-new.php?action=add-site

Does anyone have any advice?

Thanks,
Rob