Data Source Names and 64-Bit Operating Systems
To build and run an application as a 32-bit application on a 64-bit operating system, you must create the ODBC data source with the ODBC Administrator in %windir%\SysWOW64\odbcad32.exe.
A 64-bit Windows operating system has two odbcad32.exe files:
%SystemRoot%\system32\odbcad32.exe is used to create and maintain data source names for 64-bit applications.
%SystemRoot%\SysWOW64\odbcad32.exe is used to create and maintain data source names for 32-bit applications, including 32-bit applications that run on 64-bit operating systems.