Comment 4 for bug 528724

Got the same error. Stack trace is:

PS D:\documents\Petrik\documents\software\stylecopexplorer\code\unstable\v1>
bzr externals-add 'D:\repository\dev\tools\moq' tools/moq
Add external branch D:\repository\dev\tools\moq tools/moq
bzr: ERROR: zlib.error: Error -3 while decompressing data: incorrect data check

Traceback (most recent call last):
 File "bzrlib\commands.pyo", line 853, in exception_to_return_code
 File "bzrlib\commands.pyo", line 1055, in run_bzr
 File "bzrlib\commands.pyo", line 661, in run_argv_aliases
 File "bzrlib\commands.pyo", line 665, in run_direct
 File "bzrlib\cleanup.pyo", line 122, in run_simple
 File "bzrlib\cleanup.pyo", line 156, in _do_with_cleanups
 File "C:/Program Files (x86)/Bazaar/plugins\externals\commands.py",
line 80, in run
 File "bzrlib\commands.pyo", line 1159, in run_bzr_catch_user_errors
 File "bzrlib\commands.pyo", line 1055, in run_bzr
 File "bzrlib\commands.pyo", line 661, in run_argv_aliases
 File "bzrlib\commands.pyo", line 665, in run_direct
 File "bzrlib\cleanup.pyo", line 122, in run_simple
 File "bzrlib\cleanup.pyo", line 156, in _do_with_cleanups
 File "C:/Program Files (x86)/Bazaar/plugins\externals\commands.py",
line 202, in run
 File "bzrlib\builtins.pyo", line 1232, in run
 File "bzrlib\bzrdir.pyo", line 1182, in sprout
 File "bzrlib\repository.pyo", line 1704, in fetch
 File "bzrlib\decorators.pyo", line 194, in write_locked
 File "bzrlib\repository.pyo", line 3438, in fetch
 File "bzrlib\fetch.pyo", line 83, in __init__
 File "bzrlib\fetch.pyo", line 109, in __fetch
 File "bzrlib\fetch.pyo", line 137, in _fetch_everything_for_search
 File "bzrlib\repository.pyo", line 4279, in insert_stream
 File "bzrlib\repository.pyo", line 4380, in _locked_insert_stream
 File "bzrlib\repository.pyo", line 1563, in commit_write_group
 File "bzrlib\repofmt\pack_repo.pyo", line 2314, in _commit_write_group
 File "bzrlib\repofmt\pack_repo.pyo", line 2174, in _commit_write_group
 File "bzrlib\repofmt\pack_repo.pyo", line 1476, in autopack
 File "bzrlib\repofmt\pack_repo.pyo", line 1516, in _do_autopack
 File "bzrlib\repofmt\groupcompress_repo.pyo", line 693, in
_execute_pack_operations
 File "bzrlib\repofmt\pack_repo.pyo", line 761, in pack
 File "bzrlib\repofmt\groupcompress_repo.pyo", line 478, in
_create_pack_from_packs
 File "bzrlib\repofmt\groupcompress_repo.pyo", line 461, in _copy_text_texts
 File "bzrlib\repofmt\groupcompress_repo.pyo", line 402, in _copy_stream
 File "bzrlib\groupcompress.pyo", line 1704, in _insert_record_stream
 File "bzrlib\groupcompress.pyo", line 438, in get_bytes_as
 File "bzrlib\groupcompress.pyo", line 538, in _prepare_for_extract
 File "bzrlib\groupcompress.pyo", line 151, in _ensure_content
error: Error -3 while decompressing data: incorrect data check

bzr 2.1.1 on python 2.5.4 (Windows-Vista-6.1.7600)
arguments: ['C:\\Program Files (x86)\\Bazaar\\bzr.exe',
'externals-add', 'D:\\repository\\dev\\tools\\moq', 'tools/moq']
encoding: 'cp1252', fsenc: 'mbcs', lang: None
plugins:
 bookmarks C:\Program Files (x86)\Bazaar\plugins\bookmarks [unknown]
 bzrtools C:\Program Files (x86)\Bazaar\plugins\bzrtools [2.1.0]
 explorer C:\Program Files (x86)\Bazaar\plugins\explorer [1.0.1]
 externals C:\Program Files (x86)\Bazaar\plugins\externals [1.3.0]
 launchpad C:\Program Files (x86)\Bazaar\plugins\launchpad [2.1.1]
 netrc_credential_store C:\Program Files
(x86)\Bazaar\plugins\netrc_credential_store [2.1.1]
 news_merge C:\Program Files (x86)\Bazaar\plugins\news_merge [2.1.1]
 qbzr C:\Program Files (x86)\Bazaar\plugins\qbzr [0.18.4]
 rebase C:\Program Files (x86)\Bazaar\plugins\rebase [0.5.5]
 svn C:\Program Files (x86)\Bazaar\plugins\svn [1.0.2]
 upload C:\Program Files (x86)\Bazaar\plugins\upload [1.0.0dev]
 xmloutput C:\Program Files (x86)\Bazaar\plugins\xmloutput
[0.8.7.dev]

*** Bazaar has encountered an internal error. This probably indicates a
   bug in Bazaar. You can help us fix it by filing a bug report at
       https://bugs.launchpad.net/bzr/+filebug
   including this traceback and a description of the problem.