In case I try to compile any C or C++ file with the toolchain unpacked from i686-w64-mingw32-gcc-4.7.1-1-release-win32_rubenvb.7z on my Windows 7 x64 installation I got cc1.exe or cc1plus.exe segfault ("blabla had stopped working..." dialog appears). Don't know if these toolchains work on 32bit host as I haven't got any on hand to do a test.
Assuming that any win32 executable is expected to work properly on win64 through WoW layer it seems to me that something is wrong with this toolchain build.
This is outdated toolchain now. Please use latest one from download section.