“This plugin does not have a valid header…”

After uploading a plugin via the WordPress uploader, I’m given the option to activate it. Though, I get an error message saying “This plugin does not have a valid header.” and this occurs with every plugin I try.

Then, I’m forced to hit the back button and the previous page now says it cannot install the plugin because the directory already exists. So I navigate to the “Plugins” panel and it doesn’t appear.

The only solution I’ve found is then deleting the plugin files and manually re-uploading it via FTP. Then it will appear without error directly in the “Plugins” section and I can activate it.

I’m wondering if anyone else experiences this issue? And if so; has anyone found a solution? It appears to be a clear WordPress bug, but it’s so central to the plugins arena I would have suspected it would have been resolved.