Hi,
If the popups do not open, it's either your template which doesn't support Joomla 3 popups (and in that case, you can change the "popup mode" setting of the HikaShop configuration to "mootools" to circumvent the issue of your template), or because of a javascript error preventing the javascript of the popups from being initialized ('TypeError: el_show is null' is not something in HikaShop but from something else on your website and since you didn't provide any link to the page nor a user account to access it, we can't analyze it to tell you from where it's coming or if a potential fix is possible).
The solution that Xavier provided was only for the checkout as the address selector system has not been ported to the address edition but that is just a way of circumventing the problem with the popup. The problem is not in HikaShop and the address edition popup of the user manager are working just fine for everyone else which is why we are no rushing this portage.