Microsoft's example doesn't seem to be very good. I've been using SFU for a while. But I had SP1 installed first. Possibly things were worse on an early version of the OS or something. The thing is though, while I can cause the problem to occur, I can't find an example of the problem that requires cat32 to solve. I can always solve the problem with just plain pld cat.

This fails for me:

( net.exe users ; cat excerpt ) | cat

Because we are writing into the second cat process, the net.exe process and the first cat process are writing to the same pipe. Both simply write, neither opens it. This is what fails. A unix process cannot write to an open pipe after a windows process has written to it. (excerpt is just a file I had laying around.)

So the idea is to use:
( net.exe users|cat32 ; cat excerpt ) | cat

But now net.exe is writing to a different pipe. And no one else needs to write to that particular pipe. We can switch pipes by just using an extra cat command:

( net.exe users|cat ; cat excerpt ) | cat

So I can't find an example where cat32 is absolutely required. *shrug*