MultiSite Network Setting Snafus

Greetings. Am trying to complete the installation of Multi-Site.

I read: We recommend you change your siteurl to everybodyloves.com before enabling the network feature. It will still be possible to visit your site using the www prefix with an address like http://www.everybodyloves.com but any links will not have the www prefix.

I went into general settings and attempted to remove the http://www, but when I tried to save it said "not a valid URL." This was both in site URL and WP URL.

Am I in the wrong admin panel?

Please help. TYVM.

Cheers. - Frank