ODBC on Windows 2008 64 bit machine

It’s important to understand which kind of DSN you have. On an x64 system, you can create an ODBC connection(DSN) on the 32-bit side of the system or on the 64-bit side of the system.
32-bit applications will only see ODBC connections created in the 32-bit side, and 64-bits applications will only see ODBC connections from the 64-bit side. Each kind of application has is own registry.To setup DSN for 32-bit application you must use:
%WINDIR%\SysWOW64\odbcad32.exe
and for 64-bit application you must use:
%WINDIR%\System32\odbcad32.exe
There is not 32-bit edition of Windows XP on the XP Pro x64 media.
http://support.microsoft.com/kb/942976/en-us
A 64-bit version of the Microsoft Windows operating system includes the following versions of the Microsoft Open Database Connectivity (ODBC) Data Source Administrator tool (Odbcad32.exe):
• The 32-bit version of the Odbcad32.exe file is located in the %systemdrive%WindowsSysWoW64 folder.
• The 64-bit version of the Odbcad32.exe file is located in the %systemdrive%WindowsSystem32 folder.
The Odbcad32.exe file displays the following types of data source names (DSNs):
• System DSNs
• User DSNs