duplicity hangs while incremental backup on 42GB file

Hi,

I am currently trying to do a incremental backup off my system. Duplicity stops working (even after a day).
Always on the same 42GB large file.
Output is:
--------
Last inc backup left a partial set, restarting.
Last full backup date: Fri Oct 18 15:59:06 2013
RESTART: Volumes 24 to 24 failed to upload before termination.
         Restarting backup at volume 24.
Restarting after volume 23, file home/daniel/VirtualBox VMs/win7 2/win7 2.vdi, block 15950
---------
I tried restarting it serveral times, but It always stops working on the same block 15950.
Note that the first full backup always works.

This is the top output while duplicity is hanging :
------
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
14174 root 20 0 78540 30m 3988 R 99.9 0.4 0:27.00 duplicity
----

I noticed this bug about half a year ago. My only sulution was deleting the whole backup dir and start
with a full backup again.

Version: 0.6.22
Calling with:
duplicity \
 --include /etc \
 --include /home \
 --include /root \
 --include /var \
 --include /usr/share \
 --exclude /var/tmp \
 --exclude /home/daniel/jd \
 --exclude '**' / \
 file:///wd/backup/