I had the same bug, but i found that someting was set wrong in the user module administration In the ACP.
If you have mypage listed there, then edit it.. In my case it was set as Modul. It should be set as Categori, with no upper module.
Hope it helps..
I have a question about characters in mypage. I am from Denmark, and therefore has æ,ø,å
When i write something in mypage and there is a character that is not english, then i get a Mysql error.
Has anyone figured out how to make it work with non English characters?
Update..
If you are using characters other than the English alphabet, then you probably have to change the Db collation entry from latin1_swedish_ci to utf8_bin. It works for me anyway..

Mgb67