It's the freaking mod_security module in Apache. I can't believe it's still not fixed after several years. Ask your host to disable it for you.

Will this be resolved if I upgrade to 4.1.3?

No, you need to disable mod_security

So will this be resolved with the next version or will we always need our host to disable the mod_security rule?

It's not the app's fault that some third party tool breaks it. AFAIK mod_security blocks all requests with "whatever=http" string in URLs, that's just stupid.

well, my host just whitelisted the same rule we had a problem with last time and I'm still getting the error... suggestions?

***UPDATE***

This appears to be worse than previously thought. Not only can I not save in the Blog Preferences page but I also can't switch to Expert mode in the post edit screen...major suxor.

Please help!

Ethan5150 wrote:

well, my host just whitelisted the same rule we had a problem with last time and I'm still getting the error... suggestions?

***UPDATE***

This appears to be worse than previously thought. Not only can I not save in the Blog Preferences page but I also can't switch to Expert mode in the post edit screen...major suxor.

Please help!

Switch to a better host whose server security doesnt rely on mod_security P:

On the other hand, mod_security is widely use by over-protective, limiting web hosts.
Have you been able to find a solution to this

Looks like they were able to determine which mod_security rule was getting tripped and they disabled it. So far so good...