Running a Cpp/MFC program compiled as Win32 using Visual Studio 2008 on a Windows 7 64 bits?

Question

I compiled a Win32 CPP/MFC program using VS2008 running on a 64 bit Windows 7. All system dll's are linked dynamically.

This program reads/writes HKLM\Software\ subkeys. Tested on Windows 7 64 bits ok. All entries were read as expected from the HKLM\Software\Wow6432Node subnode.

The problem started when I tried running this exe on a 32 bits Windows XP machine.

The program seemed to REQUIRE the same HKLM\Software\Wow6432Node to be present i.e. it does not read from the HKLM\Software\ subkeys.

I thought registry redirection only affects Win32 programs on 64 bit machines. Why is the Wow6432Node entry still needed on the Windows XP?