I was working on a database and suddenly, after trying to install some OCA's account-fiscal-rule module, my server stopped working and i got the following error:

ParseError: "External ID not found in the system: base.menu_definitions" while parsing /home/yannick/odoo/odoo8/addons/project_issue/project_issue_view.xml:5, near

<menuitem id="menu_project_confi" name="Issues" parent="base.menu_definitions" sequence="2"/>

I haven't changed anything on project_issue module code. I tried to open up another database that I have, and I got the same error. Anyone has a clue about what happend and how can I solve it?