Issues changing to www version of domain with WP 2.7 = 404

When attempting to modify my WP install URL from https://ravensnation.com to https://www.ravensnation.com in the general settings tab of WP Admin in 2.7, I immediately receive a 404 error upon trying to save. I then cannot access the site, and have been forced to reinstall WP twice because I cannot figure out why this is happening.

This is also causing the www version of my site to generate a 404. The only way to currently access it is through the non-www version.

I would like to have the sites primary URL to be the www version for consistency and SEO purposes.

Has anyone encountered this and if so what was your solution?