Contenido does not support creating modules in clients where no language has been set up.
It is possible to break the entire module section for these clients and there is no way to recover from within Contenido's GUI.
Steps to reproduce:
Create new client.
Go straight to modules (do not set up any language).
Click on "New module".
Click on "Modules" tab to refresh module view.
The newly created module can not be deleted from file system.It may also stay in database. You get an internal error page in module list frame.
Either support modules on clients with no languages or disable creation of modules.