Plugins won't activate

Hi, I think this is a great site with lots of great plugins and themes but I'm having trouble installing some of the plugins. I downloaded multiple premium plugins and unzipped them, dragged the directories to the plugins directory of my wordpress installation, and batch selected them in the network admin plugin panel. Unfortunately, when I clicked activate nothing happened. I also tried individually activating the plugins, but that didn't work either. Am I missing something?

Thank you in advance,
Christian