I know this is an old thread but I want to post this as it may help someone else. Took me a long time but I finally figured out what causes this error message: (at least in my case)
Error in InitializeUI:
TypeError: pageMatch has no properties
If you have anything entered into the form action parameter it will throw this error.
<form id="signup_form" name="signup_form" method="post" action=""> is fine
<form id="signup_form" name="signup_form" method="post" action="anypage.php"> will result in this error.
Only way I could get around it was to set action="" or comment out anypage.php, set the Progress bar, and then set action= back to what I wanted.
Took a long time to figure this out. Hope that maybe it helps someone else save a little time. And I assume this is a bug that WA could fix as well but at least there is a workaround for it.