Error Cannot convert XMLList@5967b21 to Date

To convert XMLList date to date, first convert it to String then the date string into Milliseconds using the Date.parse method. Then you can convert the seconds to Date object

Ex: var dateString:String = xmlDateValue.toString();
var dateInMilliseconds:Number = Date.parse(dateString);
//date format "Wed May 4 15:30:17 GMT-0700 2011"
var curDate:Date = Date(dateInMilliseconds);