After successfully testing duplicity on one of our workstations, it seemed likely to be a good fit for off-site backups of our OS X server machine. However, despite having seemingly gotten it installed, I've been unable to successfully run a backup; in general, they seem to stall out while generating deltas, as below with -v9, and I'm not sure where to look next. Any pointers would be appreciated; my Google-fu has not turned up anything particularly helpful. I did anonymize the arguments (swapped valid arguments for bogus ones after pasting) but I don't think I changed any of the strings in a way that should affect execution.
duplicity 0.7.02 (March 11, 2015)
Args: /usr/local/bin/duplicity -v9 --full-if-older-than 14D --s3-use-multiprocessing --s3-use-new-style --encrypt-key=63E5CD88 --sign-key=46559EC7 --include=/Volumes/.../OUR FILES/OUR MARKETS/COOS COUNTY, NH/ --exclude=** /Volumes/.../OUR FILES/OUR MARKETS s3+http://s3path.fqdn.com/server-bak/
Darwin server.discoverymap.com 13.4.0 Darwin Kernel Version 13.4.0: Wed Dec 17 19:05:52 PST 2014; root:xnu-2422.115.10~1/RELEASE_X86_64 x86_64 i386
/usr/bin/python 2.7.5 (default, Mar 9 2014, 22:15:05)
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)]
Using temporary directory /var/folders/1k/g25fvmqd4m9dd8028gvmgtfr0000gn/T/duplicity-nuACnC-tempdir
Registering (mkstemp) temporary file /var/folders/1k/g25fvmqd4m9dd8028gvmgtfr0000gn/T/duplicity-nuACnC-tempdir/mkstemp-LW5yfi-1
Temp has 592369008640 available, backup will use approx 34078720.
Local and Remote metadata are synchronized, no sync needed.
0 files exist on backend
2 files exist in cache
Extracting backup chains from list of files: 
Last full backup date: none
Last full backup is too old, forcing full backup
Connecting with backend: BackendWrapper
Archive dir: /Users/administrator/.cache/duplicity/3c2f71ac2b6a6596c2ce67ab107b03c7
Found 0 secondary backup chains.
No backup chains with active signatures found
No orphaned or incomplete backup sets found.
PASSPHRASE variable not set, asking user.
GnuPG passphrase for signing key:
Using temporary directory /Users/administrator/.cache/duplicity/3c2f71ac2b6a6596c2ce67ab107b03c7/duplicity-SIDYK3-tempdir
Registering (mktemp) temporary file /Users/administrator/.cache/duplicity/3c2f71ac2b6a6596c2ce67ab107b03c7/duplicity-SIDYK3-tempdir/mktemp-PNVWOG-1
Using temporary directory /Users/administrator/.cache/duplicity/3c2f71ac2b6a6596c2ce67ab107b03c7/duplicity-FvTsKj-tempdir
Registering (mktemp) temporary file /Users/administrator/.cache/duplicity/3c2f71ac2b6a6596c2ce67ab107b03c7/duplicity-FvTsKj-tempdir/mktemp-iQNRNf-1
AsyncScheduler: instantiating at concurrency 0
Registering (mktemp) temporary file /var/folders/1k/g25fvmqd4m9dd8028gvmgtfr0000gn/T/duplicity-nuACnC-tempdir/mktemp-FXh03c-2
Selecting /Volumes/.../OUR FILES/SELECTED MARKETS
Comparing . and None
Getting delta of (. dir) and None