UnicodeDecodeError in startup.py

[yet]

ajung@blackmoon:~> /opt/calibre/ebook-convert "/tmp/tmpgNAe6z.html" "/tmp/tmpWE9ws8.epub"
1% Converting input to HTML...
InputFormatPlugin: HTML Input running
on /tmp/tmpgNAe6z.html
Language not specified
Creator not specified
Title not specified
Building file list...
Traceback (most recent call last):
File "/tmp/init.py", line 48, in <module>
File "/home/kovid/build/calibre/src/calibre/ebooks/conversion/cli.py", line 250, in main
File "/home/kovid/build/calibre/src/calibre/ebooks/conversion/plumber.py", line 745, in run
File "/home/kovid/build/calibre/src/calibre/customize/conversion.py", line 211, in __call__
File "/home/kovid/build/calibre/src/calibre/ebooks/html/input.py", line 286, in convert
File "/home/kovid/build/calibre/src/calibre/ebooks/html/input.py", line 337, in create_oebbook
File "/home/kovid/build/calibre/src/calibre/ebooks/oeb/base.py", line 409, in __init__
File "/home/kovid/build/calibre/src/calibre/ebooks/oeb/base.py", line 437, in namelist
File "/usr/lib64/python2.6/os.py", line 294, in walk
for x in walk(path, topdown, onerror, followlinks):
File "/usr/lib64/python2.6/os.py", line 284, in walk
if isdir(join(top, name)):
File "/home/kovid/build/calibre/src/calibre/startup.py", line 103, in my_join
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 82: ordinal not in range(128)