Wordpress - Plugin not showing in dashboard

If the plugin headers are correct, then the only option that comes to my mind is that the owner and permissions of the plugin file or its directory (if it is in one) are incorrect and WordPress cannot read the plugin file. Other than simply being logically important, if you check the source you can see that the Core specifically checks whether the plugin files are readable.

See the following for the appropriate settings: http://codex.wordpress.org/Changing_File_Permissions
http://codex.wordpress.org/Hardening_WordPress https://wordpress.stackexchange.com/a/96454/21376