Page not found when pressing accept on the 'user registration requests' sub-tab and email transport is not configured.

2012-07-18 16:55:13,932 ERROR [javax.enterprise.resource.webcontainer.jsf.application] org.nuxeo.ecm.core.api.ClientException: Error while sending mail :
javax.faces.el.EvaluationException: org.nuxeo.ecm.core.api.ClientException: Error while sending mail :
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
at javax.faces.component.UICommand.broadcast(UICommand.java:387)
at org.nuxeo.ecm.platform.ui.web.binding.alias.UIAliasHolder.broadcast(UIAliasHolder.java:86)
[...]
Caused by: org.nuxeo.ecm.core.api.ClientException: Error while sending mail :
at org.nuxeo.ecm.user.registration.UserRegistrationComponent.sendValidationEmail(UserRegistrationComponent.java:433)
at org.nuxeo.ecm.user.registration.UserRegistrationComponent$RegistrationAcceptor.run(UserRegistrationComponent.java:268)
at org.nuxeo.ecm.core.api.UnrestrictedSessionRunner.runUnrestricted(UnrestrictedSessionRunner.java:156)
at org.nuxeo.ecm.user.registration.UserRegistrationComponent.acceptRegistrationRequest(UserRegistrationComponent.java:519)
at org.nuxeo.ecm.user.registration.actions.UserRegistrationActions.acceptRegistrationRequest(UserRegistrationActions.java:165)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[...]
Caused by: javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
nested exception is:
java.net.ConnectException: Connection refused: connect
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1282)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:370)
at javax.mail.Service.connect(Service.java:275)
at javax.mail.Service.connect(Service.java:156)
at javax.mail.Service.connect(Service.java:105)
at javax.mail.Transport.send0(Transport.java:168)
at javax.mail.Transport.send(Transport.java:98)
at org.nuxeo.ecm.user.registration.UserRegistrationComponent.generateMail(UserRegistrationComponent.java:466)
at org.nuxeo.ecm.user.registration.UserRegistrationComponent.sendValidationEmail(UserRegistrationComponent.java:431)
... 116 more
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
[...]