YUI Compressor and configured downloads for 1.5.3

When I try to create a configured download including the "UI core" I
get an invalid ZIP file (with some html in the beginning), or just a
YUI Compressor error if I try the "UI core" alone.
I think it's because of special characters in the contributors' names.
When I run YUI Compressor on my machine I need to add '--charset=utf8'
to the command line to make it work.