New plugins not showing up

Hello all,
I just uploaded 3 plug-ins, amazonify, amazonadmin and social links and now none of those are showing up in my blog when I go to the admin area and select Plugins. This is strange. I certainly have other plug-ins that I’ve installed here. In fact, these 3 plug-ins were uploaded to the plugins folder of 3 separate wordpress blogs on 3 separate domains. All 3 had the same effect.
Can anyone help with any advice or information, please?
Bruce