Try to disable mod_security in Apache. Also please post a link to your blog.

My blog is http://www.workwhiledrunk.com

Oh and I've contacted my hosting. I'm pretty sure mod_security is installed and its v2, so that would mean only they can disable it or change the rules.

This wasn't a problem with b2evo 3.x though, so really b2evo needs to be fixed so mod_security can be enabled and do tis job.

Just see if disabling mod_security helps. Also you need to remove the lightbox plugin since it breaks all JS on your website. The plugin is extremely outdated.

This is fixed now. My server admin disabled mod_security just for my domain on the server, but wasn't especially happy about doing so. So if B2evo is ever changed so this is no longer required i can make him happy again by telling him to re-enable it.