"Not a valid win32 application" on Windows XP

I still use a Thinkpad T61p laptop w. Windows XP. I would like to put Panda3d on it.
I researched the older versions, & XP versions, and found the pages to d/l the “1.10” 32 bit versions.
I tried 1.10.6, and 1.10.4 SDK’s. Both of them emphasized they were for 32 bit XP. The installers listed what they would install, and they specifically stated they had Panda-specific 32-bit versions of Python.

Both installed successfully.

But when I tried to run samples, each provoked a Windows announcement that “this is not a valid Win32 application”.

I verified that the installer set the PATH correctly.

I opened a command window and tried to manually launch ppython. Got the same announcement.

Is it possible that someone accidentally packed the 64-bit version of Python in these packages?

Has anyone else experienced this? I have searched “high & low” and found nothing.