joomla 1.0.15 Cookies must be enabled. login problem

The Problem;
Using login on our home page ( not admin - that works fine ) on the first attempt I get the message 'Cookies must be enabled!' - on the second sometimes third attempt it goes blank but has accepted as when returning to the screen I'm logged in. This is the same for me on FF and IE but Safari doesn't allow at all.


The solution:

I found the solution in this post http://forum.joomla.org/viewtopic.php?f=36&t=268622&start=60

there are many things to try, this is what worked for me.

edit configuration.php. Change the $mosConfig_live_site to have the "www". For Example - http://yourdomain.com becomes http://www.yourdomain.com.