i work currently on a custom report on odoo 8 (self hosted) and created a report structure based on this tutorial: http://odoo.guide/report-design-workshop/
generally the template is created well but when I start zu use e.g.
<span t-field="o.partner_id"/>
The pdf-print crashes and returns an gigantic error text. The last sentence tells me something about, so far I understood this, that the connection between invoice and template is not available.
QWebException: 'NoneType' object has no attribute '_fields'
Im not sure where this error comes from and how i could fix it :/ Hope you can help me