I just tested this again with the latest Lucid update - desktopcouch 0.6.4.-0ubuntu3 - still no luck. I get the same errors as before :(

Command line output:

tom@MUMBLE:~$ gwibber

** (gwibber:15553): WARNING **: Trying to register gtype 'WnckWindowState' as enum when in fact it is of type 'GFlags'

** (gwibber:15553): WARNING **: Trying to register gtype 'WnckWindowActions' as enum when in fact it is of type 'GFlags'

** (gwibber:15553): WARNING **: Trying to register gtype 'WnckWindowMoveResizeMask' as enum when in fact it is of type 'GFlags'
Apache CouchDB has started, time to relax.
WARNING:root:Pid file does not contain int: '\n\n'
WARNING:root:Pid file does not contain int: '\n\n'
WARNING:root:Pid file does not contain int: '\n\n'
WARNING:root:Pid file does not contain int: '\n\n'
WARNING:root:Pid file does not contain int: '\n\n'
WARNING:root:Pid file does not contain int: '\n\n'
ERROR:root:Starting couchdb failed on try 0
Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/desktopcouch/start_local_couchdb.py", line 251, in start_couchdb
    pid, port = run_couchdb(ctx=ctx)
  File "/usr/lib/python2.6/dist-packages/desktopcouch/start_local_couchdb.py", line 132, in run_couchdb
    raise RuntimeError("Can not start couchdb.")
RuntimeError: Can not start couchdb.
WARNING:root:Pid file does not contain int: '\n\n'
Apache CouchDB has started, time to relax.
WARNING:root:Pid file does not contain int: '\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n'
ERROR:root:Starting couchdb failed on try 1
Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/desktopcouch/start_local_couchdb.py", line 251, in start_couchdb
    pid, port = run_couchdb(ctx=ctx)
  File "/usr/lib/python2.6/dist-packages/desktopcouch/start_local_couchdb.py", line 132, in run_couchdb
    raise RuntimeError("Can not start couchdb.")
RuntimeError: Can not start couchdb.
WARNING:root:Pid file does not contain int: '\n\n\n\n'
Apache CouchDB has started, time to relax.
WARNING:root:Pid file does not contain int: '\n\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n\n\n'
WARNING:root:Pid file does not contain int: '\n\n\n\n\n\n\n'
ERROR:root:Starting couchdb failed on try 2
Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/desktopcouch/start_local_couchdb.py", line 251, in start_couchdb
    pid, port = run_couchdb(ctx=ctx)
  File "/usr/lib/python2.6/dist-packages/desktopcouch/start_local_couchdb.py", line 132, in run_couchdb
    raise RuntimeError("Can not start couchdb.")
RuntimeError: Can not start couchdb.

etc. - it tries several times to bring up the couch...

Interesting side note: 

It was said above that the the PID file contains the port number, however, my PID file is completely empty except for several line breaks that are written during the startup process of the couch service (you can see the number of \n occurences growing in the command line output above. 

Ubuntuone is working ok for me since today - before it would not let me register the machine, but now this is working, so I do not think both issues are related.