[Setup] Plone 3.1 - my folder has dissapeared

[Victor Sterpu]

"My Folder" has dissapeared.
In security, the "Enable User Folders" checkbox is checked.

In the zope interface, at the "/Plone/portal_actions/user/My Folder" I have a condition:
python: member and portal.portal_membership.getHomeFolder()

I tested and the portal.portal_membership.getHomeFolder() returns false.

If I delete this part of the condition, My Folder appears, but is not working. I receive a "this page does not exist" error.

How can I fix this problem?
I did not upgraded from a older plone.
My folder does not apper for old users or for new users.

Thank you.