Support

Mandatory information about my setup:

Have I read the related troubleshooter articles above before posting (all)?
Have I searched the tickets before posting? yes
Have I read the documentation before posting (troubleshooting?)? yes
Joomla! version: 2.5.6
PHP version: 5.4.5
MySQL version: 5.0.95-log
Host: 1 and 1
Akeeba Backup version: 3.6.3

EXTREMELY IMPORTANT: Please attach a ZIP file containing your Akeeba Backup log file in order for us to help you with any backup or restoration issue. If the file is over 2Mb, please upload it on your server and post a link to it.

Description of my issue:
Backup Failed
The backup operation has been halted because an error was detected.
The last error message was:
AJAX Loading Error
HTTP Status: 500 (Internal Server Error)
Internal status: error
XHR ReadyState: 4
Raw server response:
Receive the above error after upgrading php 5.4.5 from php 5.2.17. Dropping back to the earlier version restores full function.

Backup had been running flawlessly through multiple updates of Joomla from v1.6 and through multiple upgrades of Akeeba Backup.

Fails in Firefox and in Chrome.

Do you have enough disk space on your host? Yes, 624.00 Mb used of  250,000.00 Mb available
How much is your part size for split archives? 2047.52MB
Have you tried running the Configuration Wizard again? Yes, several times.
Which of the troubleshooting instructions' steps (please list the numbers) have you followed? 1-7 see below.
Make sure that your hosts PHP memory_limit is at least 16Mb. Limit is 90Mb.
Find the Temporary directory setting and set it to [DEFAULT_OUTPUT] Retry backup. Backup failed

Needed a backup so switched back to 5.2.17 and it ran perfectly.

As a first step set the minimum execution time to 1 second. Maximum was set to 7 and execution bias was set to 75%. Backup ran fine. Please close the ticket.
Thanks