Hi, Im using a twitter plugin to get a twitter feed working on my website. It works great on all browsers but on Internet Explorer the post date displays as "NaN days ago". Has anyone else had this problem? My code where the date is being drawn from is:

Code:
function twitter_time_since(datetime)
{
    var tTime=new Date(datetime);
    var cTime=new Date();
    var sinceMin=Math.round((cTime-tTime)/60000);
    if(sinceMin==0)
    {
        var sinceSec=Math.round((cTime-tTime)/1000);
        if(sinceSec<10)
          var since='less than 10 seconds ago';
        else if(sinceSec<20)
          var since='less than 20 seconds ago';
        else
          var since='half a minute ago';
    }
    else if(sinceMin==1)
    {
        var sinceSec=Math.round((cTime-tTime)/1000);
        if(sinceSec==30)
          var since='half a minute ago';
        else if(sinceSec<60)
          var since='less than a minute ago';
        else
          var since='1 minute ago';
    }
    else if(sinceMin<45)
        var since=sinceMin+' minutes ago';
    else if(sinceMin>44 && sinceMin<60)
        var since='about 1 hour ago';
    else if(sinceMin<1440){
        var sinceHr=Math.round(sinceMin/60);
    if(sinceHr==1)
      var since='about 1 hour ago';
    else
      var since='about '+sinceHr+' hours ago';
    }
    else if(sinceMin>1439 && sinceMin<2880)
        var since='1 day ago';
    else
    {
        var sinceDay=Math.round(sinceMin/1440);
        var since=sinceDay+' days ago';
    }
    return since;
};