[Users] Use of GeocoderComboBox

[John, Steffen]

Hi All!

I want to use the GeocoderComboBox from GeoExt and facing someproblems.
I want to integrate it in a Ext.TabPanel and all I get is  following
error:
"TypeError: b[(intermediate value)] is not a constructor"

Here ist the code-snippet

 panel =  new Ext.TabPanel({
                            renderTo: Ext.getBody(),
                            activeTab: 0,
                            defaults: {
                                plain: true,
                                frame : true
                            },
                            items: [{
                                xtype: 'panel',
                                title: this.addresssearchText,
                                height : 302,
                                
                                items:[{
                                   layout:'form',
                                   items:[{
                                        xtype: 'gx_geocodercombo',
                                        layer: locationLayer,
                                        map: map,
                                        width: 200        
                                   }]
                               }]
                               },{
                               // xtype for all Component
configurations in a Container
                               title: this.coordsearchText,
                               html: 'The second tab'
                            }]
                    });

Do I need to import or reference the sourceCode of this ComboBox or
should it be accessible, when also other GeoExt functions are used in
the project?

I'm about to extend Geoexplorer and add the functionality of geocoding.

Any Ideas?

Thanks a lot!

Steffen