Why always error mail configuration when installing module anything ? (with check load demonstration data)

error :

2013-04-11 10:24:11,236 8243 ERROR oerp7_demo openerp.addons.base.ir.ir_mail_server: Mail delivery failed via SMTP server 'localhost'. SMTPServerDisconnected: Connection unexpectedly closed Traceback (most recent call last):
File "/home/i-white/OpenERP/openerp7/openerp7/openerp/addons/base/ir/ir_mail_server.py", line 459, in send_email smtp = self.connect(smtp_server, smtp_port, smtp_user, smtp_password, smtp_encryption or False, smtp_debug) File "/home/i-white/OpenERP/openerp7/openerp7/openerp/addons/base/ir/ir_mail_server.py", line 244, in connect connection = smtplib.SMTP(host, port) File "/usr/lib/python2.7/smtplib.py", line 249, in __init__ (code, msg) = self.connect(host, port) File "/usr/lib/python2.7/smtplib.py", line 310, in connect (code, msg) = self.getreply() File "/usr/lib/python2.7/smtplib.py", line 361, in getreply raise SMTPServerDisconnected("Connection unexpectedly closed") SMTPServerDisconnected: Connection unexpectedly closed 2013-04-11 10:24:11,238 8243 ERROR oerp7_demo openerp.addons.mail.mail_mail: failed sending mail.mail 1 Traceback (most recent call last): File "/home/i-white/OpenERP/openerp7/openerp7/openerp/addons/mail/mail_mail.py", line 293, in send mail_server_id=mail.mail_server_id.id, context=context) File "/home/i-white/OpenERP/openerp7/openerp7/openerp/addons/base/ir/ir_mail_server.py", line 473, in send_email raise MailDeliveryException(_("Mail delivery failed"), msg) MailDeliveryException: (u'Mail delivery failed', u"Mail delivery failed via SMTP server 'localhost'.\nSMTPServerDisconnected: Connection unexpectedly closed")