Hi,
What happened in my case was that Firefox automatically adds a number to the file when you download it for the second time. Which I did. So now the zip file was called ‘plugin(1).zip’. Which caused the trouble. When I went to CPanel and the sp-resources directory and I removed the 1, it worked okay. Everything was back to normal and the plug in works too.
And that is the root of the issue. WordPress is supposed to remove the zip after the plugin has been unzipped and moved to its correct location but fails to do so meaning a secondary download of the same plugin results as you describe.
It’s all healed. I called in the big guns for help 🙂 Thanks for your help. I appreciate it!!!!