Please advise as not able to proceed again on this.
Imported extension from below link:
https://extensions.xwiki.org/xwiki/bin/view/Extension/Administration+Application
As the error suggests, your problem is that the author of that page (the user who modified its content last) does not have enough right anymore to execute the script it contains. From what I can see in your screenshot that user (Admin) seems to not exist at all anymore (otherwise there could be a link on “Admin” leading to that user), did you delete it ?
Can you guide on Confluence migration without license … which extensions to be installed? I need to perform import of Confluence backup into xwiki and see how it looks.
As this is a common error when importing whole xwiki exports and so on (threads like these continuously pop up in the help section).
Even logging in with the superadmin account it cannot be fixed (easily?) as the setting to change wiki owner ship is inside the - by that point broken - admin section.
An script to fix things from the shell or maybe an setting in the xwiki.cfg like „fix ownership“ that changes the ownership to the superadmin would be an great help.
Otherwise it could be maybe beneficial if the admin section and other core extensions are ALWAYS owned by the superadmin and that this cannot be changed neither manually or by import to prevent this problem.