date widget not working properly

hello,

 When I change any date the format of date will be change and when saved record following traceback throws.

2012-04-24 10:06:54,385 12120 ERROR None openerp.sql_db: bad query: update sale_order set "date_order"=E'Fri Apr 27 2012 00:00:00 GMT+0530 (IST)',write_uid=1,write_date=(now() at time zone 'UTC') where id IN (8)
Traceback (most recent call last):
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/sql_db.py", line 212, in execute
    res = self._obj.execute(query, params)
DataError: time zone "gmt+0530" not recognized
LINE 1: update sale_order set "date_order"=E'Fri Apr 27 2012 00:00:0...
                                           ^

2012-04-24 10:06:54,386 12120 ERROR None openerp.osv.osv: Uncaught exception
Traceback (most recent call last):
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/osv/osv.py", line 121, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/osv/osv.py", line 176, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/osv/osv.py", line 164, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/home/sgo/workplace/rdtools/addons/trunk-contract-apa-imp-sgo/sale/sale.py", line 383, in write
    return super(sale_order, self).write(cr, uid, ids, vals, context=context)
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/addons/base/ir/ir_needaction.py", line 163, in write
    write_res = super(ir_needaction_mixin, self).write(cr, uid, ids, values, context=context)
  File "/home/sgo/workplace/rdtools/addons/trunk-contract-apa-imp-sgo/mail/mail_thread.py", line 91, in write
    write_res = super(mail_thread, self).write(cr, uid, ids, vals, context=context);
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/osv/orm.py", line 3920, in write
    'where id IN %s', upd1 + [sub_ids])
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/sql_db.py", line 152, in wrapper
    return f(self, *args, **kwargs)
  File "/home/sgo/workplace/rdtools/server/trunk/openerp/sql_db.py", line 212, in execute
    res = self._obj.execute(query, params)
DataError: time zone "gmt+0530" not recognized
LINE 1: update sale_order set "date_order"=E'Fri Apr 27 2012 00:00:0...
                                           ^

2012-04-24 10:06:54,389 12120 ERROR None openerp.netsvc: time zone "gmt+0530" not recognized
LINE 1: update sale_order set "date_order"=E'Fri Apr 27 2012 00:00:0...

Thank you.