Have you tried just downloading each file by itself? I live out in the sticks and my internet is by WiFi (through 6 hops) and I can only reliably download one file at a time. And even then I will sometimes get an error, but re-downloading fixes it.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13