Well, found some curious here.
in the db under vb_settings varname : vw_enabled grouptitle vw_server_settings value field was after the upgrade empty.
i put a 1 in the value field , save it. And when i open my wiki, it says wiki is deactivated.
So i open up the adminpage for the Wiki, it says wiki is acitvatet, so i click save. And the settings are ok. But the wiki is still inactive.
don't understand that.

settings says yes, and the wiki says no

drives me crazy
well, just test something more.
it is still activated , like settings in the adminpage says, and you click NO and save the page, it saves the new value.
if you click YES and save the page, it writes nothing into the databese, and it still says NO after redirect to the settings.
Looked into the database : vw_enabled vw_server_settings value field is empty.