[plt-scheme] Problem with mzc

I have started playing with plt mzscheme. I should like to extend mzscheme 
(and later mred) with a C++ file that uses a C++ library.
Now when I compile and link the first "hello world" program from "Inside 
MzScheme" it is compiled but not linked as __gc_personality_v0 is missing.

I called the file hw.cpp instead of hw.c.

 I have had this error before and it is a C++ problem. What can I do? I use 
Cygwin (and gcc3.2).

TIA,
-- 
Janos Blazi