[Moo] new Tips: struggling with error

[mmjaeger]

Hello,
I'm getting the following error when hovering over my elements:
b.getParent is not a function
[Break on this error] this.timer=this.hide.delay(this.options....f(!b)
{return;}parentNode=b.getParent();\n

this is the code I use:
setTips: function() {
                var els = $$('.ellipsis a');
                if (els.length < 1) return false;

                new Tips(els, {
                        text: function(item) {
                                var str = item.get('href');
                                str = str.substring(str.lastIndexOf('/')+12);
                                return str.replace('_',' ');
                        }
                });
        }

Hope somebody discovers what I'm missing

Thank you for your help.