I’m having the same problem, on 3.1.2. I only get this part of the error:
ERROR: Could not generate a WordPress export file.
Version/Server info:
[INFO] BackWPup version 3.1.2; A project of Inpsyde GmbH
[INFO] WordPress version 3.7.1
[INFO] Blog url: ———
[INFO] BackWPup job: Master Backup; DBCHECK+DBDUMP+FILE+WPEXP+WPPLUGIN
[INFO] BackWPup cron: 0 2 * * *; Next: Fri, 21 Mar 2014 @ 02:00
[INFO] BackWPup job started manually
[INFO] PHP ver.: 5.4.4-14+deb7u3; apache2handler; Linux
[INFO] Maximum PHP script execution time is 30 seconds
[INFO] Script restart time is configured to 30 seconds
[INFO] Script restarts on every main step is activated
[INFO] MySQL ver.: 5.5.31-0+wheezy1
[INFO] curl ver.: 7.26.0; OpenSSL/1.0.1e
I’ve tried adjusting the execution time from 0, to 30, 45, 90, 100 … nothing helps. Any other ideas?