All SDE kits supports both 32 and 64 bit applications. You can use the same sde.exe (on Windows) for both.
But SDE no longer support Windows XP, you should use Windows 7 or newer.
I am indeed SDE developer.
We are running sde.exe version 7.49 on Windows 7 32 bits and it works well.
Can you please send me the screen shot of the error you are seeing?
are you running command line or Cygwin?
Sergey, I'm not sure what you're trying to accomplish with these posts. You've been told that SDE (the newer versions of it) do not support Windows XP (32 or 64-bit). Obviously, this won't change, and no screenshots from XP will change that. If you want to keep using XP then you'll have to stick with the older versions of SDE as well, with all the consequences.
If you have problems in 32-bit Windows 7 or later, as your initial post and the title suggests, then I think it would be beneficial to post screenshots from Windows 7.
PS: Also, the tone of your messages is certainly not helpful. You may not like that your platform is no longer supported, but that is hardly unexpected for a platform that has long reached EOL. You can't expect it to be supported forever.