Wubi 9.04 rev129 crashes near end of install with UnicodeDecodeError

Wubi runs without problems, then dies at the very end of the installation. By "dies", I mean that the Wubi window simply disappears, no error message shown.

The last lines of the log file indicates that character set problems remain, akin to bug 344151:

...
04-24 22:37 DEBUG TaskList: ## Finished choose_disk_sizes
04-24 22:37 DEBUG TaskList: ## Running create_preseed...
04-24 22:37 ERROR TaskList: 'ascii' codec can't decode byte 0xf8 in position 5: ordinal not in range(128)
Traceback (most recent call last):
  File "Z:\home\evan\bzr\wubi.trunk\build\wubi\files\lib\wubi\backends\common\tasklist.py", line 196, in __call__
  File "Z:\home\evan\bzr\wubi.trunk\build\wubi\files\lib\wubi\backends\common\backend.py", line 578, in create_preseed
UnicodeDecodeError: 'ascii' codec can't decode byte 0xf8 in position 5: ordinal not in range(128)
...

I gather this is is a regression due to Wubi 9.04 being rewritten in Python. Wubi is unfortunately not the first Python program to choke on my name. :-/