Problem with making posts in Firefox and IE 7 on XP….

Okay, so I can make posts on my laptop using the beta Firefox 3, and IE 7 or 8, but when I go to school, I try to make posts using firefox 2.0.13, and IE 7, and I get this error:

Your attempt to edit this post: "Capcom’s approach to advertising Okami on the web" has failed.

Please try again.

Can anyone help me? Thanks!