[plt-scheme] s->s: string cannot be encoded for the current locale

Hello,

I've just built MzScheme from CVS sources and get the following error on start up:

Welcome to MzScheme version 299.23, Copyright (c) 2004 PLT Scheme, Inc.
s->s: string cannot be encoded for the current locale: "PLTCOLLECTS"
exception raised by exception handler: s->s: string cannot be encoded for the 
current locale: "mzlib"; original exception raised: s->s: string cannot be 
encoded for the current locale: "PLTCOLLECTS"

Any ideas on how I can fix this?

This is on a i686 Debian (2.2.18pre21 #1) machine.

Thanks,
David