Hi pcmonk, how did you remove the iptables errors? If you just removed the lines that are causing the errors, then you may have removed lines intended to redirect ports. If you post your iptables script here, maybe I or another user can figure out the syntax errors. My guess, not having looked at the script, is that you're missing the "-p " before "tcp".
You probably already fixed the second issue… "GenericJDBCException: Cannot open connection" is probably because you have an hung process still running. You can use "ps auwwx | grep java" to check for hanging alfresco java processes, and kill them before attempting to start up alfresco.