I have the same problem and it seems like many people also have it for a long time.
For navigation page permission issue, monobook template creator told us
here that it's related to "Display Wiki Page" for Dokuwiki plugin. On the other hand, author of that plugin claims
here that it's related to the source of Dokuwiki. He reported a bug (as he tells
here) but that bug can't be found in the
website with the message: "
task does not exist". I wonder what happened to that task.
I am really confused. If there is not a solution for this, could the authorities kindly tell us that it's a known bug and there is not any solution yet, so at least people can stop wasting time by searching for it. Thanks in advance!