Copy/paste from the forums:
Some notes on one person's experience with deploying the Samba PDC appliance.
1. Deployment was to an existing Win2000 Active Directory network managed by two DCs already; applicance hosted as Ubuntu in an Oracle VirtualBox on Win7 Pro machine
2. The boot configuration screens take in domain ID and so on;
3. Using either webmin or command line "net ads join -U Administrator" failed, "host not configured as member server"
4. I noticed that there was no /etc/krb5.conf , so no Kerberos.
5. Used package manager to install Kerberos; did a kinit of Adminstrator; still no luck
6. Using the native windows server AD admin functions, add a computer account for Samba machine's name andm make its primary "Domain Controllers"
7. Check with "net ads testjoin" - all's well now; oddly the step of "net ads join" was not repeated.
8. Verify the DC using nbtstat on a different network computer...it's not the master browser, and it's a BDC.
9. Back it up
About two hours of debugging overall. Price was right, since this is less expensive than a dedicated bare-metal solution.