[plt-scheme] PLT mzscheme 299.207 on Sharp Zaurus

Hello,

I recently tried to crosscompile PLT mzscheme (Version 299.107) for
the Sharp Zaurus. I had to disable the FFI and use the Senora GC
and tweak the Makefile, but ended up with what seemed to be 
a working executable. When I executed it on the Zaurus, I got the 
following error message:

bash-2.05$ /opt/QtPalmtop/plt/bin/mzscheme
Welcome to MzScheme version 299.107 (sgc), Copyright (c) 2004-2005 PLT 
Scheme, Inc.
> (require (lib "1.ss" "srfi"))
hash-table-put!: expects type <mutable hash-table> as 1st argument, 
given: #<hash-table>; other arguments were: #<module-registry> 
#<hash-table>

It seems as if something is wrong with the build, as the same
expression works under the natively compiled version.

Can anyone explain what's going on?
Many thanks in advance,

Alex