Magento – System backup not working

This is kind of a shot in the dark, but is there a file called maintenance.flag in the root of your Magento installation folder? If so, delete it and everything should work.

I solved the problem that had ruined my store. It was appearing error 503 and lot of errors from the processor.php file. I've deleted the maintenance.flag file from root dir, and now works.

So the rollback isn't needed.

Thanks for your time.