The code:

from openerp.osv import osv,fields

class school(osv.osv):
    _name = "school"
    _description = "school information"
    _columns = {
        'school_name': fields.char('School Name', size=30,required=True),
        'address': fields.char('Postal Address', size=50 , required=True),
        'city': fields.char('City', size=30, required=True),
    }

school()

and the view:

<?xml version="1.0" encoding="utf-8"?>
    <openerp>
    <data>
        <record model="ir.ui.view" id="school_base_form">
            <field name="name">school.form</field>
            <field name="model">school</field>
            <field name="arch" type="xml">
                <form string="School" version="7.0">
                    <field name="school_name"/>
                    <field name="address"/>
                    <field name="city"/>
                </form>
            </field>
    </record>

        <record model="ir.actions.act_window" id="action_school_form">
            <field name="name">school</field>
            <field name="res_model">school</field>

        </record>
<menuitem name="School Management" id="school_menu" />
<menuitem name="Schools" parent="school_menu" id="schools_menu" action="action_school_form" />
</data>
</openerp>

The same error... Where is the damn bug?

you should remove the line

<field name="type">form</field>

Also line

<field namme="address"/>

should be replaced by

<field name="address"/>

In the log file normally there is a more detailed description of the error.

res_model in action should have the same model name.

<field name="res_model">school</field>

I had the same problem today. I think the xml parser cannot understand lines like:

<field name="adress"/>

You should try:

<field name="address" />

Look at the space before the / ...

I hope that solves your problem :-)