I try to install new plugins (doesn't matter which one) to any WP website on the server from WP admin, and I receive the error:
Installing Plugin: Empty Tags Remover 1.0
Downloading install package from http://downloads.wordpress.org/plugin/empty-tags-remover.zip…
Unpacking the package…
Installing the plugin…
Warning: array_keys() expects parameter 1 to be array, boolean given in .../wp-admin/includes/class-wp-upgrader.php on line 189
The package could not be installed. The plugin contains no files.
Plugin install failed.Down
WP is able to download the zip folder into to the .../wp-content/upgrade folder, but then cannot proceed to install it.
Could it be a WP issue or incompatibility with PHP or MySQL?
WordPress version 3.3.1
PHP version 5.3.10
MySQL version 5.1.61