Originally Posted by euain
You can try to see what is using the port - in a terminal netstat -a will tell you what ports are in use, lsof -i4 (I think - but you might want to check the man page) will tell you what is using each port.
It may be that you need to stop some other service/program as there is a clash.
It must be a flaw in the program. I looked at both of those and didn't see either of the ports in use. I guess I'll send in a bug report.
Thanks everyone. I'll keep you updated.