These builds need a x86_64 system (also called AMD64 or EM64T) and produce x86_64 or (-m32) x86 (ia32) programs.
Please remember to also set an LD_LIBRARY_PATH and/or compile the programs statically (or use -rpath) as otherwise your program may not find the libgfortran.so library.
If you get the error version `GLIBC_2.4' not found (required by .../gcc-trunk/lib64/libgmp.so.3)
, you can try the libgmp.so from http://www.lps.ens.fr/~dominiq/gmp/libgmp.so.3.bz2 instead.