No valid plugin found.

downloaded developer version.

I have the same problem.
I use WordPress 3.9.1

I tried to instal this plugin twice and it told me that there was an installation error. I am running the most up-to-date version of WordPress.

Create a folder in your /plugins called /wp-artists-lite
Then upload the files in the /trunk folder to /wp-artists-lite via ftp
Now you can activate in plugins in admincenter