If the file path is correct and the CreateProcess returns no error that
would indicate a couple of possible issues:-
Is the cab file the correct processor version for the device? (arm, mips,
sh3 etc)
Is the application already installed? (see the settings > remove programs
applet)
Does the cab file install correctly when manually tapped by the user in File
Explorer?
However, a strange thing happens. I cannot find wceload.exe in my Pocket PC
Windows directory using File Explorer. Instead, it shows up if I use my
desktop computer's Windows Explorer. Why is that?
That's expected behavior. Your first path had spaces in it, so you must
enclose the full filename and path in a quote delimiter so wcesload.exe
knows to use the entire string.