The package could not be installed. PCLZIP_ERR_MISSING_FILE (-4) : Missing archive file 'C:\WINDOWS\TEMP/akismet.tmp

When WordPress downloads a plugin ZIP file, then it has to be able to write that file somewhere. To do this, it uses C:\WINDOWS\TEMP directory.

If WP detects that it cannot write files to this temp directory, then you get the error message like "The package could not be installed. PCLZIP_ERR_MISSING_FILE (-4) : Missing archive file 'C:\WINDOWS\TEMP/akismet.tmp " .

Solution:

You can work around this by specifying a temp directory on your server with a place that you know WordPress is allowed to write files to. You can do this by adding this line of code into the wp-config.php file.

1. Find the links blow:

if ( !defined('ABSPATH') )
    define('ABSPATH', dirname(__FILE__) . '/');

2. Add lines below
/** Specify wordpress temp dir */
define('WP_TEMP_DIR', ABSPATH . 'wp-content/temp');

3. Open wp-content folder, and create a new folder named "temp"

Try again, you will see it works like a charm.