I don't know if this is the same bug, but there seems to be another concurrency-related issue showing up in LPs svn imports.  the 'zope.password' import is now failing[1] with the tracceback:

2010-05-10 17:06:46 INFO    Starting job.
2010-05-10 17:06:46 INFO    Getting exising bzr branch from central store.
2010-05-10 17:06:57 INFO    35 bytes transferred | 
2010-05-10 17:06:59 INFO    
2010-05-10 17:06:59 WARNING Upgrade to svn 1.5 or higher for faster retrieving of revision properties.
Traceback (most recent call last):
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/scripts/code-import-worker.py", line 82, in <module>
    sys.exit(script.main())
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/scripts/code-import-worker.py", line 77, in main
    return import_worker.run()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/lib/lp/codehosting/codeimport/worker.py", line 437, in run
    return self._doImport()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/lib/lp/codehosting/codeimport/worker.py", line 571, in _doImport
    foreign_branch_tip = foreign_branch.last_revision()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/branch.py", line 501, in last_revision
    last_revmeta, mapping = self.last_revmeta()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/branch.py", line 256, in last_revmeta
    for revmeta, mapping in self._revision_meta_history():
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/util.py", line 142, in next
    return self._next()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/util.py", line 124, in _next
    ret = self._iterator.next()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/repository.py", line 825, in _iter_reverse_revmeta_mapping_history
    (mapping, lhs_mapping) = revmeta.get_appropriate_mappings(mapping)
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/revmeta.py", line 344, in get_appropriate_mappings
    original = self.get_original_mapping()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/revmeta.py", line 843, in get_original_mapping
    self._original_mapping = self.base.get_original_mapping()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/revmeta.py", line 372, in get_original_mapping
    revprops_acceptable=revprops_acceptable)
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/revmeta.py", line 683, in _import_from_props
    if revprops_acceptable(revprops):
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/revmeta.py", line 367, in revprops_acceptable
    return revprops.get(SVN_REVPROP_BZR_ROOT) == self.branch_path
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/util.py", line 67, in get
    self._ensure_init()
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/util.py", line 29, in _ensure_init
    self.dict = self.create_fn(*self.args)
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/logwalker.py", line 206, in _caching_revprop_list
    self.cache.insert_revprops(revnum, revprops, True)
  File "/srv/importd.launchpad.net/production/launchpad-rev-9329/optionalbzrplugins/svn/cache/sqlitecache.py", line 392, in insert_revprops
    self.cachedb.executemany("replace into revprop (rev, name, value) values (?, ?, ?)", [(revision, name.decode("utf-8", "replace"), value.decode("utf-8", "replace")) for (name, value) in revprops.iteritems()])
sqlite3.OperationalError: database is locked
Import failed:
Traceback (most recent call last):
Failure: twisted.internet.error.ProcessTerminated: A process has ended with a probable error condition: process ended with exit code 1.

[1] https://code.launchpad.net/~ztk-steering-group/zope.password/trunk