When I try to upgrade or install a plugin I get a successful message:
Downloading install package from http://downloads.wordpress.org/plugin/jquery-lightbox-gallery.zip… Unpacking the package… Installing the plugin… Successfully installed the plugin Fancy Gallery 1.0.27. Activate Plugin | Return to Plugin Installer`
If however I have a look via ftp in my plugins directory the plugin has not been installed and the new plugin folder does not exist.
Then when I click the
Activate Plugin link I get the following error
The plugin does not have a valid header. which is not surprising considering the plugin hasn't been installed.
This happens no matter which plugin I try to install. It's strange because I have several other wordpress installations on the same host, and infact two other separate wordpress installations on the same domain and I have never had this problem.
I tried re-uploading a fresh installation of wordpress over the top of the current one and there was no change. I tried deactivating every single plugin and switching to the basic theme but it still didn't work. Any help would be greatly appreciated!
Update: So I tried making a new FTP account, and I can now add plugins using this new account. However when I try to upgrade a plugin I still get a
Could not remove the old plugin. Plugin update failed. error.