jquery.cookie.js doesn't load on some servers.

Some servers do not load the jquery.cookie.js file correctly, and return a 407 error. This can be fixed by renaming the file to something like jquery.c00kie.js. For some reason, probably related to security measures, certain servers reject the request because the file’s content type isn’t that expected for a request for a cookie.

http://wordpress.org/plugins/contact-form-plugin/