The duplicity application cannot handle FTP timeouts, it always crashed if one occures. To fix this issue, a patch has been submittet in the patch tracker of the duplicity project: http://savannah.nongnu.org/patch/?func=detailitem&item_id=5183 since no newer release has been made so far, this patch has to be applied manually. The ebuild should do this, IMHO. (for duplicity-0.4.2, the patch does not work but the backend.py file provided works.)
I wanted to wait until upstream approves this patch and includes it in the code, but seeing as upstream is de facto dead, I'll include this patch into our package in few hours, when I'm back from work.
I've created a diff from the backends.py file from above URL, and it gets applied in recently committed 0.4.2-r1. Feel free to reopen this bug if it doesn't work properly - I've tested it somewhat though, and it seems to work as advertised. Thanks for reporting!
