Using AT&T Network Client VPN with Ubuntu 64bit

(This post is probably of most interest to my IBM colleagues - however, since the AT&T Network Client is also available for other organisations, I’ve posted this here in case it’s of use to other folks.) I recently installed Ubuntu 64bit (amd64) on my Lenovo Thinkpad T61. Unfortunately, the Network Client is not available in a 32bit edition. So I had to perform a few tweaks to get it to work.