I've been looking through the forums for a solution to the 'The plugin does not have a valid header' issue. It appears to be a common issue but I am experiencing different symptoms...
I get this error with every single plugin I attempt to install and activate. I get the message saying it has downloaded succesfully but when I click on 'activate' I get the error message.
Upon checking my ftp site the plugin folder is there but when I go back to WordPress the plugin (whichever one I attempted) just is not there.
So, it downloads ok, but does not activate or show up in WordPress, which is version 3.5.
Is anyone else experiencing these symptoms?