My Pagelines theme CSS is broken on the wp-signup.php page with this plugin. When I deactivate it, the page returns to normal.
I have turned it back on so you can see. Go to http://icatsbeta.com/wp-signup.php to check it out. The page should be centered and the header and navbar are not styled. Here's a picture to show what it should look like - http://icatsbeta.com/?wpdmdl=8&ind=0.