It is also empty in the Outgoing Email in the Technical Features(if you remove the filter in the search box?)

Yes, all the e-mails sent about payment reminders are also without attachments. I have updated the above comment to include more information about this particular part. Here is a bigger resolution version of the picture: http://i.imgur.com/uNT4Zcp.png

I have just set up a new database, installed the necessary modules, made some test products, invoices and clients and started testing with payment reminders. From a fresh install, I seem to have no difficulties with this at all. They are sent properly and with template/attachment. I will now backup and try to uninstall / reinstall and reconfigure this app in my production-database.

After reinstalling the Payment Follow-up management, my payment reminder levels were reset to default values. The e-mail templates also reverted to their original settings. Yet when I send my payment reminders they are still empty.

It is notable that in my test-database the body was filled in under my outgoing e-mails. Under my production-database this hasn't yet been the case.

Can you recommend what other modules I have to un- / reinstall to try and revert the payment reminder functionality back to default? That seems to work under a fresh install. I'd hate to lose all my content though

Updating all the accounting modules after each other, and de- / reinstalling the payment follow-up app isn't proving helpful. It's strange it's working out of the box, but no longer functioning on my database. My database is already in production, so I'm tyring to see what I can do to salvage my data in a new database. (restore from production) I just can't afford to re-enter all my products, clients, orders and invoices - let alone all the tweaking of the settings and translations.

I uninstalled all the accounting modules, the e-mail gateway, email templates and anything related. By extension the sale and purchase management were also uninstalled. This was all done on a separate testing-database. After these changes all my orders and invoices were gone, but I still could not send my payment reminders properly. So basically I reinstalled everything that seemed related, after having uninstalled those modules - and it still doesn't work. Not that it would be a good solution, but if this doesn't work I have no idea what might be related to the problem... Any help appreciated

Small detail: in your first screen it says: betaalherinnering (betalingsherinnering or even something else would be better). In the mail it says: Relance de paiement. First time, it is in Dutch, second in French. Maybe check the language of your partners as it is the language of your mail: ${object.lang}. Probably your French translation is empty.

I would not recommend uninstalling modules and reinstalling btw. Updating does enough normally. (or you could remove the template and then update, that way the original template should appear)

@Josse: I found the problem. It wasn't exactly what you described, but your comments did lead me to the solution. I'm very grateful for your support, and taking the time to read up on my case.

In the end it was something really silly. I had previously de-activated the English language, as we don't want to use this language for our clients. Setting this language back on active allowed the body of my payment reminder emails to come through. So it was just this one little checkbox that caused trouble. I feel rather stupid, but I figured I'd share this in case anyone else has a likewise issue.