It sounds similar to this:
though that says it was fixed for 2.5.1.
If you turn debugging can you see any output on the redirect page
If you are running Apache you could try a work around of using a .htaccess file for the interim, something along the lines of this:
using that Apache would do the redirect, moodle would never see the "www" version of the URL.
Hi Jet et al.
I think it must be a simpler solution than that. I turned on Debugging on full, and there was no output on this page. I simply get this page, which then redirects. FYI, I'm accessing the page via www.gravyforthebrain.com/moodle - as you can see, it's complaining about the www. part, even though wordpress is running on www. and DNS is set up (as well as the SSL) for www.