Redmine

Ocorre o erro abaixo quando tento acessar por exemplo uma issue:
http://<site.com.br>/redmine/issues/1

ActionView::TemplateError (missing interpolation argument in "%A, de %B de %Y, %H:%M hs" ({:object=>Mon, 12 Jul 2010 14:52:29 BRT -03:00} given)) on line #23 of app/views/welcome/index.rhtml:
20: < for project in Projects Projects >
21: < Herve Harster = project >
22: <li>
23: <= link_to_project project > (<= format_time(project.created_on) >)
24: <= textilizable project.short_description, :project => project >
25: </li>
26: < end %>