how long did it take for you using the first script? just because you said the second script would be slower it made me think something was wrong on my version if option 2 was (slow) but still much faster to get a result. was hoping that if there was indeed something wrong with my version, it might get fixed then it would be a much faster process.
The success/unsuccess and speed of the extract images tool is related to the PDF thumbnail handler installed in the system. I've tested the most common PDF readers thumbnail handlers and the fastest with your PDF file is the provided by the Sumatra PDF reader. The one with the pdf-xchange viewer is also good.
Both cut, roughly, in half the time taken by the ImageMagick based script.
To test with the Sumatra PDF reader, if your Windows is 64-bit, install the 64-bit version and also the 32-bit version (to a different folder e.g. C:\Program Files (x86)\SumatraPDF) and then, from an elevated command prompt, run the command regsvr32 "C:\Program Files (x86)\SumatraPDF\PdfPreview.dll".
