I ran into that problem a few years ago.
I made my own copy of TLHelp32 which works for Delphi (I use Delphi 2) and FPC.
In case you might find it useful, I attached it to this post. Actually, what is attached is an example program that uses toolhelp to determine the bitness and subsystem of every program running in the system. Note that you may get a warning about being unable to acquire the debug privilege if you run the program as a normal user. Full source and project included (along with the copy of TLHelp32.pas you need.) Enjoy!.