406 error

Hi, I just installed shoutbox, and when I go to the admin page, I get a 406 error. "Not Acceptable
An appropriate representation of the requested resource /admin/settings/shoutbox could not be found on this server"

Any advice? I can set user permissions to see / not see/ write / admin shoutbox, and I can manipulate what settings it has, but I can't edit the block either.