win32pipe calls the GetModuleFileName Windows API to find the directory from which it was loaded and uses that to locate w9xpopen.exe (which is only needed on Windows 95/98/ME). GetModuleFileName does not work if win32pipe is loaded from an archive (i.e., bundle <= 2). This is because Windows has no knowledge of .pyd/.dll files loaded from archives because LoadLibrary is not called to load them.
In principle it should be possible to make this work. Since win32api.pyd is loaded by the LoadLibrary emulation, the loader code could patch the GetModuleHandle/GetModuleFilename functions to use the emulated functions. Whether the result will be usable for what win32pipe needs is another question.