Comment 5 for bug 520939

I get something very similar on Windows 7 using WinMerge as an external diff tool. The error dialog that I get contains the following text:

Run command: bzr diff --using "C:/Program Files (x86)/WinMerge/WinMergeU.exe" -rrevid:<email address hidden>...
=== modified file 'Core.lua'

And the bzr.log contains:

Mon 2010-02-22 20:39:35 -0500
0.039 bazaar version: 2.1.0
0.039 bzr arguments: [u'qsubprocess', u'--bencode', u'l4:diff7:--using45:C:/Program Files (x86)/WinMerge/WinMergeU.exe112:-rrevid:<email address hidden>:<email address hidden>']
0.049 looking for plugins in C:/Users/Owner/AppData/Roaming/bazaar/2.0/plugins
0.086 looking for plugins in C:/Program Files (x86)/Bazaar/plugins
0.153 encoding stdout as osutils.get_user_encoding() 'cp1252'
0.207 bazaar version: 2.1.0
0.207 bzr arguments: [u'diff', u'--using', u'C:/Program Files (x86)/WinMerge/WinMergeU.exe', u'-rrevid:<email address hidden>:<email address hidden>']
0.210 Returning RevisionSpec RevisionSpec_revid for revid:<email address hidden>
0.210 Returning RevisionSpec RevisionSpec_revid for revid:<email address hidden>
0.210 encoding stdout as osutils.get_user_encoding() 'cp1252'
16.445 Transferred: 0KiB (0.0K/s r:0K w:0K)
16.445 return code 1
59.149 encoding stdout as sys.stdout encoding 'cp437'