Re: You have to enable cookies to be able to login to this site
I've experienced the same problem.
Intermittently over the past week or so, I encountered this problem in Firefox. But if I clicked on an something on the site, such as an article, first before attempting to login, I and others were able to login.
Until today. This afternoon I couldn't log into my own site using Firefox because of this error. I was able to log in using IE8. Nothing had been changed in either browser - both permitted cookies, including 3rd party cookies.
Following norris08's suggestion, I changed the cookie path in Admin/Login to /storage/, which is where Tiki was installed by Jumpbox. I and others using the site now are able to login. I think it is too early to tell whether this has really resolved the problem.