[xwiki-users] Problem for removing or editing Workspaces

Hi all, I am trying to get a mock-up with XWiki workspaces. I have a problem, especially to remove a workspace or to make a change in the description. Each time, the Tomcat log indicates that XWiki could not verify the user rights: When I try to delete the workspace: 2012-02-16 14:02:54,068 [https://xwiki-test.domain.local/xwiki/bin/view/WorkspaceManager/DeleteWorks…] ERROR .x.w.i.DefaultWorkspaceManager - Failed to check if user [[XWiki.superadmin, informatique]] can delete workspace [java.lang.NullPointerException]. Assuming false. When I try to edit any workspace parameter: 2012-02-16 14:14:27,686 [https://xwiki-test.domain.local/xwiki/bin/view/WorkspaceManager/UpdateWorks…] ERROR .x.w.i.DefaultWorkspaceManager - Failed to check if user [[XWiki.superadmin, informatique]] can edit workspace [java.lang.NullPointerException]. Assuming false. 2012-02-16 14:14:27,692 [https://xwiki-test.domain.local/xwiki/bin/view/WorkspaceManager/UpdateWorks…] ERROR .WorkspaceManagerScriptService - Failed to edit workspace 'informatique'. org.xwiki.workspace.WorkspaceException: Access denied for user 'XWiki.superadmin' to edit the workspace 'informatique' at org.xwiki.workspace.internal.WorkspaceManagerScriptService.editWorkspace(WorkspaceManagerScriptService.java:188) ~[xwiki-platform-workspace-api-4.0-20120215.094308-2.jar:na] 2012-02-16 14:14:28,031 [https://xwiki-test.domain.local/xwiki/wiki/informatique/admin/XWiki/XWikiPr…] ERROR .x.w.i.DefaultWorkspaceManager - Failed to check if user [[xwiki:XWiki.superadmin, informatique]] can delete workspace [java.lang.NullPointerException]. Assuming false. Problem is the same with XWiki.Admin, the owner of the workspace.Beyond that,I always thought that XWiki.superadmin always had full access, regardless of the rights settings... Do I have something wrong in my config? Any help will be welcome! Thanks. -- Bertrand PUJOS IT Department - IRCAD bertrand.pujos(a)ircad.fr +33 (0) 3 88 11 91 36