DuplicateKey error inside version_file in TreeTransform: bzr: ERROR: Key is already present in map

Hi

I'm trying to merge changes from lp:~alexharrington/xibo/jclient-xmds in to a branch of lp:~alexharrington/xibo/java-client which I have locally on my machine.

The local branch is a fresh copy generated by:

bzr branch lp:~alexharrington/xibo/java-client xibo

I then
cd xibo
bzr merge lp:~alexharrington/xibo/jclient-xmds
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
bzr: ERROR: Key media.java-20081221133039-ageuhm6huuw9r25z-18 is already present
 in map

I've just finished a major refactoring in lp:~alexharrington/xibo/java-client to accomodate using Java Plugin Framework, and had to roll back on some changes, but ultimately was very careful to bzr rm, bzr move etc all the files.

I've googled on ERROR: Key is already present in map, but all I could find was a message in the irc logs which was asking for info to reproduce, hence the bug report.

Traceback:
Sun 2009-01-18 22:42:54 +0000
0.047 bzr arguments: [u'merge', u'lp:~alexharrington/xibo/jclient-xmds']
0.047 looking for plugins in C:/Documents and Settings/Alex Harrington/Application Data/bazaar/2.0/plugins
0.078 looking for plugins in C:/Program Files/Bazaar/plugins
0.109 bzr-svn: using Subversion 1.5.4 ()
0.156 opening working tree 'C:/xibo'
5.484 falling back to default implementation
5.484 failed to load system host keys: [Errno 2] No such file or directory: 'C:\\Documents and Settings\\Alex Harrington/.ssh/known_hosts'
[ 3284] 2009-01-18 22:43:00.390 INFO: Connected (version 2.0, client Twisted)
6.141 Trying SSH agent key AB471EC92902A9683EE0AAF6AB6AC6CA
[ 3284] 2009-01-18 22:43:01.280 INFO: Authentication (publickey) successful!
[ 3284] 2009-01-18 22:43:01.390 INFO: Secsh channel 1 opened.
9.953 Using fetch logic to copy between KnitPackRepository('bzr+ssh://bazaar.launchpad.net/%7Ealexharrington/xibo/jclient-xmds/.bzr/repository/')(<RepositoryFormatKnitPack1>) and KnitPackRepository('file:///C:/xibo/.bzr/repository/')(<RepositoryFormatKnitPack1>)
11.656 Traceback (most recent call last):
  File "bzrlib\commands.pyo", line 893, in run_bzr_catch_errors
  File "bzrlib\commands.pyo", line 839, in run_bzr
  File "bzrlib\commands.pyo", line 539, in run_argv_aliases
  File "C:/Program Files/Bazaar/plugins\qbzr\lib\commands.py", line 600, in run
  File "bzrlib\builtins.pyo", line 3068, in run
  File "bzrlib\builtins.pyo", line 3086, in _do_merge
  File "bzrlib\merge.pyo", line 489, in do_merge
  File "bzrlib\merge.pyo", line 461, in _do_merge_to
  File "bzrlib\merge.pyo", line 600, in do_merge
  File "bzrlib\merge.pyo", line 655, in _compute_transform
  File "bzrlib\transform.pyo", line 2401, in resolve_conflicts
  File "bzrlib\merge.pyo", line 655, in <lambda>
  File "bzrlib\transform.pyo", line 2479, in conflict_pass
  File "bzrlib\transform.pyo", line 475, in version_file
  File "bzrlib\transform.pyo", line 64, in unique_add
DuplicateKey: Key media.java-20081221133039-ageuhm6huuw9r25z-18 is already present in map

11.672 return code 3

Sun 2009-01-18 22:56:04 +0000
0.063 bzr arguments: [u'--version']
0.063 encoding stdout as sys.stdout encoding 'cp850'
0.125 return code 0