Installing on winXP SP3 error.

Tried installing Standard Edition on an old WinXp SP3 computer. When trying to start the program I get that the program isn't a valid 32-bit program.
Account is administrator and SP3 + 3.5 .net Framework is installed.

What is wrong?

/Thanks in advance

Secure Lockdown now requires .Net 4.0. Sorry that our documentation is inaccurate regarding this. It will be updated shortly.

Installed .net 4.0 and still the same error.

It seems .Net 4.5.2 is needed but that won't work with WinXP so I guess you can't use Secure Lockdown on WinXP then?