Hi Rich,
I marked the problem SOLVED in the Q&A thread, but I believe it's still a bug here, unless a developer has fixed it.
To reproduce, boot TC 4.2.1 and load Firefox, samba, and cups.
At a terminal, change the root password with "sudo passwd".
Navigate to
http://localhost:631 . Click Administration. Click Add Printer. Enter root with YOURROOTPASSWORD.
"Windows Printer via Samba" will not show up as a radio button.
Your command fixes it:
sudo ln -fs /usr/local/bin/smbspool /usr/local/lib/cups/backend/smb
I don't have the TC dev environment, but I would guess /usr/local/bin/cups-config is the relevant script.
Ben