Installing psqlODBC on 64bit Windows
Though you can install 32 bit ODBC drivers on Win X64 as usual, you can't configure 32-bit DSNs via ordinary control panel or ODBC datasource administrator.
How to configure 32 bit ODBC drivers on Win x64
Configure ODBC DSN from %SystemRoot%\syswow64\odbcad32.exe
%SystemRoot%\syswow64\odbcad32.exe
You may have to play with it and try different scenarios, think outside-the-box, remember this is open source.