Mootools Slideshow & Lightbox 2 Plugin Conflict

Dear WordPress friends,

I am debugging a WordPress site (https://nyartbar.com/wrdz/) that is using Mootools Slideshow on its Home Page. The site owner is using the Lightbox 2 plugin on a different Page of the site. With the Lightbox 2 plugin activated, Slideshow does not run in the large white space in the center of the Home Page. However, when I deactivate the Lightbox 2 plugin, Slideshow works perfectly, displaying the images. Also, when the Lightbox plugin is deactivate, no JavaScript errors appear on the Page, but when activated, the following 2 errors appear:

In prototype.js?ver=… (line 592):

this._each is not a function
each(function(), undefined)prototype.js?ver=... (line 592)
Native()mootools.js (line 15)
$each([Object], function(), undefined)mootools.js (line 15)
Native()mootools.js (line 15)
mootools.js()mootools.js (line 15)
[Break on this error] this._each(function(value) {

In calendar.js (line 1):

Element.setWidth is not a function
e(load )calendar.js (line 1)
e(load )calendar.js (line 1)
e()calendar.js (line 1)
[Break on this error] eval(function(p,a,c,k,e,d){e=function(c){return(c<a?"":e(parseInt(c/a)))+((c=c%a...

Any help would be greatly appreciated! Thank you for your time!