Not acceptable – trying to login

Hi,

I have installed WP the manual way as well as using Fantastico and both times I am getting a ‘Not acceptable’ error after clicking on the login button. Everything with installation goes perfectly, the site is live and sample page up and running, but when I go to login, all I get it this error. There is no further details on the page, just simply ‘Not acceptable’ text.

Thanks for any help!