This FAQ serves two purposes. Firstly, it does what a FAQ generally does – answer frequently asked questions. Secondly, it is also a place to dump fragments of documentation which haven’t matured enough to be moved into their own documentation file.
The answer is, as often, the nearly useless “It depends”. The built-in modules serve two purposes: On one hand, they should be ready to use and demonstrate the power of FeinCMS. On the other hand, they should be simple enough to serve as examples for you if you want to build your own CMS-like system using the tools provided by FeinCMS.
If a proposed feature greatly enhances the modules’ or content types’ abilities without adding heaps of code, chances are pretty good that it will be accepted into FeinCMS core. Anyway, the tools included should be so easy to use that you might still want to build your own page CMS, if your needs are very different from those of the original authors. If you don’t like monkey patching at all, or if the list of extensions you want to use grows too big, it might be time to reconsider whether you really want to use the extension mechanism or if it might not be easier to start freshly, only using the editor admin classes, feincms.models.Base and maybe parts of the included PageManager...
This happens when the Django model loading code encounters an ImportError when it loads the page module for the first time. The module is added to a list of postponed modules, and the import is retried after all other applications have been successfully imported. This will cause the mptt.register call to be executed twice though, which is why you see this exception. We could catch this exception and go on as if nothing had happened, but this hides a deeper problem somewhere which should be fixed for good instead of papering over the issue.
There are several ways how you might find out what’s going wrong. Raise the debugging level, try importing the page module (and other modules) from the shell you get when you use ./manage.py shell are some possibilities how you might debug this problem.
You enabled the page module (added feincms.module.page to INSTALLED_APPS), run syncdb, and afterwards registered a few extensions. The extensions you activated (datepublisher and translations) add new fields to the page model, but your first syncdb did not know about them and therefore did not create the columns for those extensions.
You can either remove the line Page.register_extensions(...) from your code or drop the page_page table and re-run syncdb. If you want to keep the pages you’ve already created, you need to figure out the correct ALTER TABLE statements for your database yourself.