Appointments+ stopped working after upgrading to version 1.5.5

Hi
The appointments page stopped working after upgrading to version 1.5.5. I have reverted back to 1.5.4 to ensure clients can continue using the site.

When we click on the 'Please click here to confirm appointment' button, nothing happens. When I turn on Firebug and click on the button, it works but as soon as I turn off firebug, nothing is happening.

Thanks
Vamsi