Magento Connect Downloader (1.4+) Unable to unpack

If you find yourself repeatedly receiving messages like:

ERROR: Unable to unpack /public_html/downloader/pearlib/download/some_awesome_module.tgz

After checking permissions (which should be right to have gotten this far) you could try the fix below.

Tar <- download this tar.php file (it’s zipped for your convenience).

Browse to downloader/pearlib/php/Archive and rename Tar.php to Tar.old

Upload the extracted Tar.php from the download above

Now Magento Connect downloads should work fine