Bug in extjs4 ext-all-debug.js

[suman.sritan]

select : document.querySelectorAll ? function(path, root, type) {
            root = root || document;
            if (!Ext.DomQuery.isXml(root)) {
            try {
                var cs = root.querySelectorAll(path); 
                return Ext.Array.toArray(cs);
            }

this is my code in Ext-all-debug.js,
the problem i am getting is "root.querySelectorAll is not a function "

please provide the solution ........

[ExtJSNinjas]

I am also seeing this caught exception quite a bit. Would it be possible to just check for querySelectorAll before trying to call it?