Error occurred while validating the field(s) arch: Invalid XML for View Architecture! while installing a module .

I tied to install a module which I developed including the warranty details of a customer.It was working fine until I added a grid structure under the form,so that the respective dates for the preventive maintenance can be scheduled.When I altered the code for this purpose the below error appears when I try to install the module. Validate Error Error occurred while validating the field(s) arch: Invalid XML for View Architecture!. I couldn't trace out the error in .xml file(perhaps in .py file also).Both the files are attached .Can anyone please help me in sorting out the error and complete my requirement of placing a grid under the form view. warranty_info_view.xml warranty.searchwarranty.warrantysearchwarranty.result.treewarranty.warrantytreewarranty.result.formwarranty.warranty

Warranty Detailswarranty.warrantyformtree,form warranty_info.py from openerp.osv import osv, fields class warranty_warranty(osv.osv): _name = 'warranty.warranty' _columns = { 'name':fields.many2one('res.partner','Customer Name'), 'contract':fields.many2one('account.analytic.account','Contract'), 'batch_no':fields.char('Batch No.'), 'status':fields.selection([('open','Open'),('close','Close')],'Warranty Status'), 'serial_no':fields.char('Serial No.'), 'notes':fields.text('Details'), } warranty_warranty() class order(osv.osv): _description = "Orders" _name = "order.order" _columns = { 'line_ids': fields.one2many('order.line','ordr_id',"Order Lines"), 'date': fields.date('Date'), 'pm_status': fields.selection([('pending','Pending'),('complete','Complete')],'Preventive Maintenance Status'), } order() class order_line(osv.osv): _description = "Order Line" _name = "order.line" _columns = { 'ordr_id': fields.many2one('order.order', 'Order ID'), } order_line()