backup GUI throws unknown bug

[Peter]

User noticed backup drive disconnected during backup. When trying to re-launch backup tools after re-mount, following error was thrown:

(see attachment)

User also edited /usr/lib/python2.7/dist-packages/duplicity/dup_time.py (ln181) to change TimeException(bad_interval_string % interval_string) to TimeException(). This led to an additional backup error: unknown duplicity version. This makes me think reading the old duplicity files is throwing this error. Can I try deleting the backup files and re-backing up to the drive without issue?

Ubuntu 14.04 LTS
Deja dupe backup tool: deja-dup 30.0-0ubuntu4

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubuntu-docs 14.04.5
ProcVersionSignature: Ubuntu 3.13.0-57.95-generic 3.13.11-ckt21
Uname: Linux 3.13.0-57-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.11
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Jul 8 15:01:42 2015
InstallationDate: Installed on 2014-11-03 (247 days ago)
InstallationMedia: Ubuntu 12.04.5 LTS "Precise Pangolin" - Release amd64 (20140807.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-docs
UpgradeStatus: Upgraded to trusty on 2014-11-12 (238 days ago)