Thanks to Jo, super-sysadmin, who pointed me at two links that finally got me connected to our work VPN after I switched from Debian to Ubuntu.  The trick is not to use the old pptp-config, but instead switch to a new package - network-manager.  Brian Daley wrote up the the actual VPN Connection instructions, and I also had to follow the advice to disable network interfaces in /etc/networking/interfaces so that the new package could manage them.  After fiddling with the VPN configuration settings (disable EAP-Authentication, and disable authenticate peer), I was able to connect.  As you can imagine, I was quite overwhelmed by the excitement.