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If what you attached is your complete backup log file, there is no chance you were up to 81%. This log file stops in the middle of the db dump, so you're somewhere before 50%. I think that you're running out of disk space. Try removing all files from your backup output directory (administrator/components/com_akeeba/backup), your temporary directory (tmp) and your cache directories (cache and administrator/cache), then retry backing up AFTER you have upgraded to Akeeba Backup 3.3.10.

I will need you to do the following:
1. Remove the contents of your tmp directory, but not the directory itself. This is perfectly safe. It's called a temporary directory for a reason: its contents are temporary, i.e. they are supposed to be deleted often.
2. Please DO check your free space. How much free space do you have on your account? Please tell me how much it is (.e.g 50Mb free out of 500Mb total)
3. Please DO upgrade to Akeeba Backup 3.3.10. If you receive an error message, please DO tell me what the error message is. The version you are using is obsolete and not supported. We first have to get you to upgrade, otherwise I can not help you.
4. After we do all of that, if the backup still fails, I need you to tell me exactly what you've tried and also ZIP and attach your new backup log file.

Please remember that I am not sitting in front of your PC and I do not have access to your site. I need you to be my eyes while trying to help you. Just posting a screen shot of the progress is just as good as posting a shot of your car's dashboard to your mechanic and asking him to tell you why the car doesn't start.

And, please, do follow all of my instructions, not only those that you feel that "should" be enough. It's very important.

OK, it now makes more sense. Please go to Extensions, Plugin Manager, find the "System - System Restore Points" plugin and disable it. Then retry the upgrade. It will no longer try to take a backup of the component before upgrading it and the upgrade will work.