When you try to update WordPress or install plugins, the downloader / installer page pops up, the compressed file is downloaded to your server, but installation fails because of this error:
PCLZIP_ERR_MISSING_FILE (-4) : Missing archive file .. tmp’
You need to access the files on your server via FTP. or the File Manager section of your control panel.
On your server, navigate to the /wp-content folder. Create a new folder inside it called TEMP.
Download and or Edit /wp-config.php from your server to your computer. Open it up in a text editor, and at the very bottom of the file
add the line
define('WP_TEMP_DIR', ABSPATH . 'wp-content/TEMP');
then save wp-config.php. Upload it to your server again if necessary.
Try updating WordPress or installing a plugin. It should work now.