OK first things first. The reason your New Admin is not working is probably because your nuke _authors table has incorrect/too many or not enough fields. Check your table and it's fields against the ones in the default package of nuke in the nuke.sql file.
As for your second problem, upgrading to chatserv's fix pack for your version of nuke should fix that. If not, check
http://www.nukefixes.com for the fix.