ASCII/Unicode error in Tailor

When using Tailor to migrate from Subversion to the Darcs distributed version control system, I encountered an error saying:

'ascii' codec can't encode character

According to this Tailor bug report, the solution is to specify the --encoding=utf-8 option to Tailor. However, that did not work for me. Instead, I had to change Python’s default system encoding, in the /etc/python2.4/site.py file, from "ascii" to "utf-8" to solve the problem.