I'm trying to capture two articles from PLOS biology. When I download this article:

http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.1000035

I get both the snapshot and the pdf.

When I try to capture this article:

http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.1000036&ct=1

I get the snapshot and a link to nowhere. I tried to download the pdfs manually and it worked, so they are available. This is happened to me a few times now and I'm not sure what is going on.

I also noticed that the following article only does snapshots:

http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.1000037&ct=1

This is different type of article, an "unsolved mystery" as opposed to a "research article". Don't know if that makes a difference.

Any ideas as to why this is happening?

Thanks!

Sanjuro