You more or less have a solution from what was posted already.
But here is my crack at giving a solution:
1. Delete the "new folder".
2. create a new folder in the plugins folder and rename it to the name of the plugin you are installing.
3. Download the plugin and extract it's files into that new folder you created.
4. Check the folder, if you see another folder instead of files then:
..a. open that folder
..b. select all the files (Edit->Select all or CTRL+A)
..c. cut the files (Edit->Cut or CTRL+X)
..d. go back to the parent folder. This should be the folder you originally created.
..e. paste files (Edit->Paste or CTRL+V)
5. Done. Restart C2 to access plugin.R0J0hound2013-02-22 19:23:00