Well, your settings seem to be ok. 3 is the Users group and 1 is for Administrators. Your $config[referer] variable looks like it is ok as well.
When you go in and edit the board(s) in question what group(s) have read/write privileges?
It might help as well to get your group # listing so I can make sure these match up correctly. To do this you can use the following mysql command:
SELECT * FROM w3t_Groups
