Support

First, please remove the file plugins/system/oneclickaction.php. It's part of the now broken Akeeba Backup installation. Then please install the version of Akeeba Backup which is appropriate for your Joomla! and PHP versions, as per our version compatibility page: https://www.akeebabackup.com/compatibility.html

Now, why did the update fail? You have tried to install Akeeba Backup 3.5.x on Joomla! 1.5. This is not possible. Akeeba Backup 3.5.x only supports Joomla! 2.5 as clearly stated in our release announcement.

Joomla! 1.5 users will still be supported for using Akeeba Backup 3.4.3 on their sites until August 2012. After that point, the Joomla! project itself will completely stop supporting Joomla! 1.5. This means that Joomla! 1.5 will become vulnerable, end-of-life software which should not be used on live sites. The Joomla! project has announced its plans for Joomla! 1.5's end-of-life back in January 2011 when Joomla! 1.6 was released. If you are receiving update emails and wish them to stop, please unpublish the System - Akeeba Backup Update Check plugin.


Side note: Joomla! 1.5 is no longer the most used Joomla! version, at least among Akeeba Backup users. The vast majority of our support tickets over the last two months and a half have been about Joomla! 2.5 sites. Prior to Joomla! 2.5's release, about 60% of the tickets were about Joomla! 1.5. This means that everyone is scrambling to upgrade their sites. One more reason not to let Akeeba Backup fall behind to satisfy the ever-shrinking minority of users who are still using Joomla! 1.5.

Support policy: Our plans for supporting different Joomla! versions have always been very well publicised in our release announcements. Please go to our release announcements page at https://www.akeebabackup.com/home/news/56-releases and click on the latest release announcement for the software you want to find the support policy for. If you just want to see which version is compatible with your Joomla! installation and whether it is supported or not, please visit our Version Compatibility page at https://www.akeebabackup.com/compatibility.html

Why do older versions report there's an update available even if it's not supported? This has to do with the Live Update system in use by our software. Older versions of Live Update were not aware of Joomla! version compatibility of available versions of our components, therefore they would report any available newer version as an update you have to install. Changing that required a major change in Live Update and our update server. The change made it in Akeeba Backup 3.5.0 and our other components released after that date. Unfortunately older versions' Live Update code cannot be updated for obvious objective reasons. Releasing updates for older Joomla! versions is also not an option, as it would cause several issues on Joomla! 2.5 sites. Therefore you just have to make sure that you have the latest available release designed for your Joomla! version, as per our Version Compatibility page at https://www.akeebabackup.com/compatibility.html and ignore Live Update's prompts for updating Akeeba Backup.

I believe I already told you what you have to do, in the first paragraph of my reply:

First, please remove the file plugins/system/oneclickaction.php. It's part of the now broken Akeeba Backup installation. Then please install the version of Akeeba Backup which is appropriate for your Joomla! and PHP versions, as per our version compatibility page: https://www.akeebabackup.com/compatibility.html

Did you try the part in bold letters?

OK, let's do a manual uninstallation of Akeeba Backup. Remove the following folders:
- administrator/components/com_akeeba EXCEPT the administrator/components/com_akeeba/backup directory and the administrator/components/com_akeeba/akeeba/serverkey.php file. If you remove that directory and that file you will lose your existing backups and/or settings.
- components/com_akeeba
- administrator/modules/mod_akadmin
- media/com_akeeba
- plugins/system/plg_srp
- plugins/system/plg_akeebaupdatecheck
- plugins/system/plg_aklazy
- plugins/system/plg_oneclickaction
Now Akeeba Backup is completely uninstalled, you should be able to log back in to your site and re-install Akeeba Backup.

OK, that's a completely different issue than the one you asked help for. In your original message you mentioned an error message. Obviously, since you've removed that file and all code files of Akeeba Backup, Akeeba Backup is no longer part of whatever is triggering the problem on your site. Have you also removed Admin Tools and any other software by us? If so, the 403 is not related to our software and I'd suggest doing this:
- Try renaming your .htaccess file
- Make sure the permissions of your folders as 0755 and your files 0644
Please note that none of our software will ever touch any of the above or do anything on your site to make it throw a 403 error without your consent. I mean you can, of course, specifically tell Admin Tools to create a .htaccess with a wrong configuration or tell it to change the permissions of files and folders, but it's not automatic and such actions require your express consent.

If the above solutions don't help, please post back.