I added a bunch of users using xmlrpc, a number of those didn't have fullname set. After a few days one of those users created a personal space: this user's space was created with SPACENAME set to NULL which caused parts of Confluence to barf with java.lang.NullPointerException errors. I guess the AddPersonalSpace should check if the user's fullname is set or not before adding the space (I fixed it by hand in the database by setting the Space's name to the user's fullname using "update SPACES set SPACENAME='<fulname>' where SPACEID=57;")