Seriously, folks, this is a packaging bug in GCC 3.4.5-vista special. Just cd to the bin directory and run "strings mingw32-g++.exe > gccstrings.txt", and open gccstrings.txt and you'll see what I mean -- there are references to paths like "d:/JDevel/MinGW", "d:/JDevel/MinGW/lib/gcc/", "d:/JDevel/MinGW/bin/", and "d:/JDevel/MinGW/libexec/gcc/".
As I was the creator of the 3.4.5-vista special package, I'm working on getting this fixed right now.