Certain PDFs won't combine

[Jude28534732bhi5]

I have need to combine a number of screen shot PDFs into single files. It works successfully for screen shots of PubMed searches, Google searches and screen shots from national adverse events databases like MAUDE. I have never been able to combine PDFs of screen shots from the Cochrane Library and now also can't combine PDFs of Google Scholar. I pay an annual subscription for an Adobe PDF pack (which looks exactly the same as the free one so I don't know why I bother). What is going on! 

[Test Screen Name]

Please tell us exactly what happens when you try and it fails. For example, a screen shot of error message. Also I suggest posting two files that don't combine, so others can test it. "Adobe PDF pack (which looks exactly the same as the free one so I don't know why I bother)." That's what you get. It looks the same but adds more functions. Though not as many as actual Acrobat.

[try67]

It looks like this:

Not a very informative error message...

[Jude28534732bhi5]

Continuing from above: the actual error message is contained in a red box and says "Could not organize". Attached below are the two sample files I used. 

[Test Screen Name]

I can confirm this happens to me if I used the online converter (which is what PDF Pack uses). I can't find anything odd about these files, nor suggest a solution, sad to say.

[try67]

The issue is most likely with how the files were produced. It does work fine in Acrobat, though.