I am pretty sure Akeeba Backup 3.7.6 does run just fine on Joomla! 2.5.10 and PHP 5.3; this is the exact combination currently used on our own site. Could you please tell me what is the exact error message you are receiving?
Furthermore, please go to your site's back-end and click on the Extensions, Extensions Manager menu item. On this page you will see a tab called "Warnings". Click on it. In the new page look for a warning which has to do with the upload size. If you see it, then your PHP upload size is too small. In this case please ask your host to set the maximum upload size to 6Mb and the maximum POST size to 10Mb in their php.ini.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
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