Javascript error not letting me use MEDIA-GRID plugin

Hi. I am not using an official http://www.ww.wp.xz.cn/themes theme, I am using a theme called Limo, and I have bought this plugin, Media-Grid, for adding a portfolio with different settings. After I add it on the website, it shows only loading and nothing else except the filters. The plugin developer told me it is a javascript error:

TypeError: document.body is null
document.body.style.webkitTouchCallout=’none’;

In an inline code, part of this script:

<script type="text/javascript">
/*<![CDATA[*/
document.onselectstart=function(){
    if (event.srcElement.type != "text" && event.srcElement.type != "textarea" && event.srcElement.type != "password") {
        return false;
    }
    else {
         return true;
    }
};
if (window.sidebar) {
    document.onmousedown=function(e){
        var obj=e.target;
        if (obj.tagName.toUpperCase() == 'SELECT'
            || obj.tagName.toUpperCase() == "INPUT"
            || obj.tagName.toUpperCase() == "TEXTAREA"
            || obj.tagName.toUpperCase() == "PASSWORD") {
            return true;
        }
        else {
            return false;
        }
    };
}
document.body.style.webkitTouchCallout='none';
/*]]>*/
</script>

He says that any portfolio/gallery I’ll use will be affected by this issue, that is related to some form fields, and with this javascript error, systems are blocked.
I can’t contact the one who created the theme, because he doesn’t answer any of the questions I addressed, even after months of waiting. I really need your help, please. Thanks in advance.

My website is http://www.efijydesigns.sitest.ro and the page where I tested the plugin is http://www.efijydesigns.sitest.ro/acasa