Could not create xml store

[Umrahi]

xml file is
<?xmlversion="1.0"encoding="utf-8" ?>
<items>
<count>5</count>
<item>
<id>1</id>
<Column>Col1</Column>
</item>
<item>
<id>2</id>
<Column>Col2</Column>
</item>
<item>
<id>3</id>
<Column>Col3</Column>
</item>
<item>
<id>4</id>
<Column>Col4</Column>
</item>
<item>
<id>5</id>
<Column>Col5</Column>
</item>
</items>

code is
storeColumns = new Ext.data.xmlStore({
url: 'Columns.xml',
totalRecords: 'count',
record: 'item',
idPath: 'id',
fields: [{name:'Col', mapping:'Column'}]
});

it throws an error called
Microsoft JScript runtime error: Object expected

Could you please help

[fay]

For a start the xml file should begin with a space between xml and version:

 
<?xml version="1.0" encoding="utf-8" ?>

and the class is Ext.data.XmlStore not Ext.data.xmlStore.

Also, I'd recommend using FireFox+FireBug for developing+debugging, before testing on other browsers - you'll get much better (verbose) error messages.