Great post and walk through. I was still having issues with it working after following the steps but here is what I did to get it to work for me.

in the file autopwn.py ( located /pentest/exploits/fasttrack/bin/ftsrc ) around line 83

change line 88
Code:
child1.sendline ('db_destroy postgres:root@localhost/pentest')
change line 90
Code:
child1.sendline ('db_connect postgres:root@localhost/pentest')
NOTE: I am using BT4 R1 release but I didn't have to uninstall / reinstall postgreSQL

hope this helps someone out there