Errro while using Ext.grid.CheckboxSelectionModel()

[Ibrahimp]

Hi ,

I'm getting the following error popup while using Ext.grid.CheckboxSelectionModel()

Microsoft JScript runtime error: Object doesn't support this action

following is the line of error -
var checkBoxSelMod = new Ext.grid.CheckboxSelectionModel();

I am not able to identify whats going wrong.:(

Appreciate your help.

Thanks,
Ibrahim
P.S - using <script src="extjs-4.1.0/ext-all.js" type="text/javascript"></script> .js library.

[redraid]

Ext.grid.CheckboxSelectionModel not exists in ExtJS4, use Ext.selection.CheckboxModel

var checkBoxSelMod = Ext.create('Ext.selection.CheckboxModel');