I have tried doing the same thing in my OpenERP client. The code is worked fine.

Python

from openerp.osv import osv,fields

class region(osv.Model):
    _name = 'region.region'
    _columns = { 
                'name': fields.char('Name', size = 100), 
                'type': fields.selection([('country','Country'),('state','State')],'Type'), 
                'country': fields.many2one('res.country', 'Country'), 
            }
region()

xml

<openerp> 
<data> 
    <menuitem id="region_main_menu" name="Regions"/>
    <record id="region_region_tree_view" model="ir.ui.view">
        <field name="name">region.region.tree</field>
        <field name="model">region.region</field>
        <field name="arch" type="xml">
            <tree string="Regions">
                <field name="name"/>
                <field name="type"/>
                <field name="country"/>
            </tree>
        </field>
    </record>

    <record id="region_region_form_view" model="ir.ui.view">
        <field name="name">region.region.form</field>
        <field name="model">region.region</field>
        <field name="arch" type="xml">
            <form string="regions" version="7.0">
                <group col="4" colspan="4">
                    <field name="name"/>
                    <field name="type"/>
                    <field name="country"/>
                </group>
           </form>
        </field>
    </record>

    <record id="region_normal_action" model="ir.actions.act_window">
        <field name="name">region</field>
        <field name="res_model">region.region</field>
        <field name="view_type">form</field>
        <field name="view_mode">tree,form</field>
    </record>

<menuitem id="section_main_menu" parent="region_main_menu" name = "Region Information"/>

<menuitem id="region_real_menu" parent="section_main_menu" action="region_normal_action"/>

</data>

</openerp>

I am attaching the form and tree view of the same. Please check it also. C:\fakepath\form_view.png C:\fakepath\tree_view.png

Thanks

Sreedath