Personaly, I have TDM 32 and 64 bits version installed and working. They are respectively installed in C:MinGW32 and C:\MinGW64 and configured like that in compilers CB base paths.
As told on TDM site, it's better to avoid C:\MinGW.
In my path they are declared as follow : C:\MinGW32\bin;C:\MinGW64\bin;... in this order.
In C::B, the 64 bits compiler versions are configured with their specific name x86_64_...
Like that it works perfectly.
gd_on