Support

Your site has PHP4. As stated, Akeeba Backup requires PHP 5. IMHO, it is of paramount importance that you upgrade to PHP 5 a.s.a.p.! PHP 4 is not supported since August 2008. That's almost 2 years which, in IT time, is equivalent to a couple of lifetimes and some more. Sticking with PHP4 is like asking your site to be hacked.

That said, if you want to live dangerously, you can simply edit your jos_modules table and delete the line which refers to mod_akadmin. This is the "Backup required" icon, which tries to auto-load parts of Akeeba Backup - that's throwing the error.

If you now have PHP 5, there is nothing to worry about. If not, you can safely try to use Akeeba, but do not enable the administrator panel module before you make sure that Akeeba Backup loads. This is the very reason it is now distributed separately from the component. I don't want to DOA my users' sites :)

The way it can happen? Simple. Most hosts who support both PHP 4 and PHP 5 will give you special directives to place in your .htaccess file to switch your site to PHP5. If you remove them, or remove .htaccess, or overwrite it with another version which doesn't have those lines, PHP 4 kicks in.

I posted my last message late at night yesterday. On second reading, it wasn't very clear what I meant, right?

Let's take it one step at a time. The Akeeba Backup distribution is split in two parts: the component (Core or Pro, doesn't matter) and the administration panel icon module (mod_akadmin). The standard procedure is:
1. Install the component
2. Try running a backup. If you get a PHP4-related error, upgrade to PHP5 and repeat this step until there is no PHP fatal error thrown.
3. Install mod_akadmin and publish it to the icon position.

The icon module (mod_akadmin) can and will lock you out of admin if you have PHP4. The reason is that in order to check for out-of-date backups it has to load Akeeba Engine's factory class, which requires PHP5. Since this happens as soon as you try to access the backend control panel, if you have PHP 4 you are effectively locked out. The easy workaround if you do get locked out:
1. Try logging in to your site's back-end
2. You get a white page or an error page. This is normal. The Control Panel can't load, but Joomla!'s session cookie is set, so you are effectively logged in.
3. Visit http://www.yoursite.com/administrator/index.php?option=com_modules Since you bypass the administrator's Control Panel page, this one loads ;)
4. Click on Administrator, find the Akeeba Backup notification module and unpublish it

You're welcome :)