CKEditor and MVC.NET

I am using CKEditor as a wysiwyg editor with my MVC.Net iste. It works when I am testing
the site locally, but when I have deployed my site to my webhost I
receive the following error when submitting the form:

A potentially dangerous Request.Form value was detected from the
client (message="<p>
Hello World</p>
").

My controller looks like the following:

[ValidateAntiForgeryToken]
[AcceptVerbs(HttpVerbs.Post)]
[ValidateInput(false)]
public ActionResult Create(Post post)
{.... }

I have read some places that I should put <httpRuntime
requestValidationMode="2.0" /> in the web.config, but since the
project runs on .Net 3.5 it doesn't work.

What really boggles my mind is that it works fine, but not when
deployed.

I have tried to set HtmlEncodeOutput = "true", thinking that should do it, but with no luck. Shouldn't HtmlEncodeOutput work on MVC.NET sites?