I hit this same bug:

$  dbus-send --session --dest=org.desktopcouch.CouchDB --print-reply --type=method_call / org.desktopcouch.CouchDB.getPort
Error org.freedesktop.DBus.Error.Spawn.ChildExited: Process /usr/lib/desktopcouch/desktopcouch-service exited with status 1
$  /usr/lib/desktopcouch/desktopcouch-service 
Traceback (most recent call last):
  File "/usr/lib/desktopcouch/desktopcouch-service", line 51, in <module>
    import desktopcouch
ImportError: No module named desktopcouch
$  dpkg -l \*desktopcouch\*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                            Version                         Description
+++-===============================-===============================-==============================================================================
ii  desktopcouch                    0.6.9b-0ubuntu1                 A Desktop CouchDB instance
ii  libdesktopcouch-glib-1.0-2      0.6.96-0ubuntu1                 Glib-based API for Desktopcouch
un  python-desktopcouch             <none>                          (no description available)
ii  python-desktopcouch-records     0.6.9b-0ubuntu1                 Transitional package, desktop CouchDB Records API
$  ls /usr/lib/python2.6/dist-packages/desktopcouch -l
total 24
drwxr-xr-x 2 root root 4096 2010-10-18 09:23 bookmarks
drwxr-xr-x 3 root root 4096 2010-10-18 09:23 contacts
drwxr-xr-x 2 root root 4096 2010-10-18 09:23 notes
drwxr-xr-x 2 root root 4096 2010-10-18 09:23 records
drwxr-xr-x 2 root root 4096 2010-10-18 09:23 replication_services
drwxr-xr-x 2 root root 4096 2010-10-18 09:23 tasks
$  sudo aptitude reinstall desktopcouch
[sudo] password for morgan: 
The following packages will be REINSTALLED:
  desktopcouch 
The following packages will be REMOVED:
  hplip-cups{u} 
0 packages upgraded, 0 newly installed, 1 reinstalled, 1 to remove and 3 not upgraded.
Need to get 63.1kB of archives. After unpacking 1,458kB will be freed.
Do you want to continue? [Y/n/?] 
Get:1 http://us.archive.ubuntu.com/ubuntu/ maverick/main desktopcouch all 0.6.9b-0ubuntu1 [63.1kB]
Fetched 63.1kB in 0s (92.7kB/s)   
(Reading database ... 207006 files and directories currently installed.)
Removing hplip-cups ...
(Reading database ... 206997 files and directories currently installed.)
Preparing to replace desktopcouch 0.6.9b-0ubuntu1 (using .../desktopcouch_0.6.9b-0ubuntu1_all.deb) ...
Unpacking replacement desktopcouch ...
Setting up desktopcouch (0.6.9b-0ubuntu1) ...
Processing triggers for python-central ...
                                         
$ ls /usr/lib/python2.6/dist-packages/desktopcouch -l
total 72
drwxr-xr-x 2 root root  4096 2010-12-16 15:31 bookmarks
drwxr-xr-x 3 root root  4096 2010-12-16 15:31 contacts
lrwxrwxrwx 1 root root    44 2010-12-16 15:31 __init__.py -> /usr/share/pyshared/desktopcouch/__init__.py
-rw-r--r-- 1 root root  5958 2010-12-16 15:31 __init__.pyc
lrwxrwxrwx 1 root root    47 2010-12-16 15:31 local_files.py -> /usr/share/pyshared/desktopcouch/local_files.py
-rw-r--r-- 1 root root 13173 2010-12-16 15:31 local_files.pyc
drwxr-xr-x 2 root root  4096 2010-12-16 15:31 notes
drwxr-xr-x 3 root root  4096 2010-12-16 15:31 pair
drwxr-xr-x 2 root root  4096 2010-12-16 15:31 records
lrwxrwxrwx 1 root root    47 2010-12-16 15:31 replication.py -> /usr/share/pyshared/desktopcouch/replication.py
-rw-r--r-- 1 root root  6478 2010-12-16 15:31 replication.pyc
drwxr-xr-x 2 root root  4096 2010-12-16 15:31 replication_services
lrwxrwxrwx 1 root root    55 2010-12-16 15:31 start_local_couchdb.py -> /usr/share/pyshared/desktopcouch/start_local_couchdb.py
-rw-r--r-- 1 root root  7956 2010-12-16 15:31 start_local_couchdb.pyc
lrwxrwxrwx 1 root root    54 2010-12-16 15:31 stop_local_couchdb.py -> /usr/share/pyshared/desktopcouch/stop_local_couchdb.py
-rw-r--r-- 1 root root   992 2010-12-16 15:31 stop_local_couchdb.pyc
drwxr-xr-x 2 root root  4096 2010-12-16 15:31 tasks
$  dbus-send --session --dest=org.desktopcouch.CouchDB --print-reply --type=method_call / org.desktopcouch.CouchDB.getPort
method return sender=:1.283 -> dest=:1.281 reply_serial=2
   int32 35237

Now desktopcouch seems to be working fine.