I wanted to follow up on this. I reinstalled to the newest version of DF and had to manually re-make the users table to get it to work. The users table was small, fortunately. All is working fine now.
I really don't know what the problem was, have you heard anything about a slight problem with the 5.3.3 version of php? Come to think of it, the calendar events only showed for the current month only - shortly after I updated to the 5.3.3 version of php. This might just be a coincidence though.