Problems with Contact Forms

Hi all WP people, I have been trying to install a contact form option to my WordPress blog v2.1 and the wp-contactform-akismet plugin seems like the best option with its built-in spam protection. I have downloaded it from bloggingexpertise.com and uploaded it to my “wp-content/plugins/” folder and activated it. But when I try to configure it at “Options >> Contact form” I get the following error message:

“Not Found
The requested URL /blog/wp-admin/wp-contact-form/options-contactform.php was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.”

Any clues of what might be wrong? This plugin is on the 2.1 compatibility list but is seems like there is something wrong – why would it look for the plugin in the “wp-admin” dir? Thanks in advance =)