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.
Yes, you read that right: the 32-bit version of the ODBC administrator is in SysWOW64 and the 64-bit one is in system32. The Control Panel gives no indication of a 32-bit version and most applications you are running on 64-bit are likely 32-bit.
– Soli Deo Gloria