Hello,
Glad you tried our software

The investigation of your problem shows that you have a sort of "scroller" installed at your store, which is assigning a page to load
itself by default, in the onLoad function on the fly. We have developed our contrib so it is defined in the body tag, but this script
is like "overwriting" the onLoad function with itself (so it will load instead of ajax checkout script) thats why you got a blank page.
So, possible solutions are:
1. Disable that scroller or uninstall it
2. Your scroller uses the "startscroll" function, which is defined somewhere in the script with the
line "window.onload=startscroll", so in this line it "overwrites" our "onLoad" function which is called "goOnLoad();".
You may alter the javascript so our functions will also be called after the scroller init, but this, however, requires you to
know javascript.
Hope it helps.