I have installed the gradebook and the new mods I did not have. Now when I go to add a new quiz I get:
Could not add a new instance of quiz
I imagine it will be the same for assignments because I read a post with a similar problem.
Moodle Ver 1.41 (Tons of mods including activity linking)
PS
In addition to this problem, I can not create a category for the gradebook
Have you visited the admin page of your moodle site afterwards?
normally it's in yoursite.com/moodle/admin/index.php
normally it's in yoursite.com/moodle/admin/index.php