Quote Originally Posted by donw View Post
Ok. From your suggestion I've replaced the html_header.php file with the 1.5.6c version, and that has gotten rid of the Mootools error, but I am now left with the following:

TypeError: el.addEvent is not a function. (In 'el.addEvent('focus', function(cal){ this.toggle(cal); }.pass(cal, this))', 'el.addEvent' is undefined) on line 454 of jscript_b-calendar.js

I've done a fair amount comparing of other files to try to find the problem, but have had no success.
I have this installed on what has now become a Zen Cart 1.5.7 site using responsive_classic primarily. Looking through the code as able, it seems that there may be an issue connecting with the box that is to represent/hold the date information. Again, need to be sure that the page validates against html and that the location to hold the date has the applicable html code to attach to the date block. That should be present in the provided checkout_shipping file at least in the modified code section.