Plugin won't appear when installed

Hello,

I recently installed Omeka 2.1.3, and wanted to install the most recent version of the Neatline plugin, but when I move the downloaded (and unzipped) Neatline folder to the /plugins directory as mentioned here 'http://omeka.org/codex/Installing_a_Plugin'
Neatline does not appear in the Plugins section of /admin so that I can install it. How can I fix this?

Thank you so much,

Nedim

I'm experiencing the same problem. Any ideas? Thanks.