404 on form submission

[eluser]xLite[/eluser]
Hello

This is really starting to annoy me and there doesn't seem to be any reason why this happens. Basically I have a form, with a <textarea> field for input. I used to be able to type whatever I like, submit the form and then the process page processes the data etc.

However, now, if the <textarea> field contains http:/ it will immediately cause CodeIgniter to show a 404 page. Why does it do that???

If anyone could shine any light onto what is happening, that would be fantastic.

So basically, as soon as http:/ is entered, CodeIgniter throws a 404 page, if I don't enter this specific phrase it just continues onto the process page.