cbtransfer crashes with Python 2.4 and couchstore-files as source

Steps to reproduce (build 170, VM to reproduce - 10.3.3.95):
1. Create default bucket and load 100k items using mcsoda.
2. Use the below command to transfer data to file:
/opt/couchbase/bin/cbtransfer -v -v -v couchstore-files:///opt/couchbase/var/lib/couchbase/data/ /tmp/backup
(there is sufficient disk space in /tmp)

Getting the below error:
[root@caper-012 ~]# /opt/couchbase/bin/cbtransfer -v -v -v couchstore-files:///opt/couchbase/var/lib/couchbase/data/ /tmp/backup
2013-03-01 03:19:31,359: mt cbtransfer...
2013-03-01 03:19:31,360: mt source : couchstore-files:///opt/couchbase/var/lib/couchbase/data/
2013-03-01 03:19:31,360: mt sink : /tmp/backup
2013-03-01 03:19:31,360: mt opts : {'username': None, 'source_vbucket_state': 'active', 'destination_vbucket_state': 'active', 'verbose': 3, 'dry_run': False, 'extra':

{'max_retry': 10.0, 'rehash': 0.0, 'nmv_retry': 1.0, 'cbb_max_mb': 100000.0, 'try_xwm': 1.0, 'batch_max_bytes': 400000.0, 'report_full': 2000.0, 'batch_max_size': 1000.0, 'report': 5.0, 'recv_min_bytes': 4096.0}

, 'single_node': False, 'bucket_destination': None, 'destination_operation': None, 'threads': 4, 'key': None, 'password': None, 'id': None, 'bucket_source': None}
2013-03-01 03:19:31,361: mt source_class: <class 'pump_sfd.SFDSource'>
2013-03-01 03:19:31,395: mt sink_class: <class 'pump_bfd.BFDSink'>
2013-03-01 03:19:31,395: mt source_buckets: default
2013-03-01 03:19:31,395: mt bucket: default
2013-03-01 03:19:31,396: mt source_nodes: N/A
2013-03-01 03:19:31,411: mt enqueueing node: N/A
2013-03-01 03:19:31,411: w0 node: N/A
2013-03-01 03:19:31,509: s0 create_db: /tmp/backup/bucket-default/node-N%2FA/data-0000.cbb
2013-03-01 03:19:31,509: s0 connect_db: /tmp/backup/bucket-default/node-N%2FA/data-0000.cbb
....................python: Objects/obmalloc.c:765: PyObject_Malloc: Assertion `bp != ((void *)0)' failed.
Aborted

With less number of items e.g. 10k, this works fine.