Try this,
We needn't mention XML root tag name here so just get rid of list
tag name when access XML.
Add resultFormat="e4x"
to HTTPService component.
<s:HTTPService id="malls" url="assets/details.xml" resultFormat="e4x"
result="malls_resultHandler(event)"/>
ml = new XMLListCollection(malls.lastResult.mallD);
To
var response:XML = malls.lastResult as XML;
var mallIDXMLList:XMLList = response.mallD;
m1 = new XMLListCollection(mallIDXMLList);