Comment #1 on issue 643 by Andreas.EbbertKarroum: [Jython] UnicodeDecodeError in OperatingSystem.List Files In Directory when File contains Umlauts
http://code.google.com/p/robotframework/issues/detail?id=643
It's a bug in Python 2.5. :( http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=481795
