ODI Debugging error

I tried to start the debugger in ODI but kept getting an error message which looked like this:

If I used Local (No Agent) the debug session would work fine. This confused me for a while since I thought everything was configured correctly. Searching the documentation I found out that the JMXPort which is used for the debugging session is set to the ODI agent port + 1000 by default. And then the penny dropped, but before I can explain what went wrong I have to explain a little bit about my test setup.

My laptop runs Windows 7 Enterprise, the database containing the ODI repository and most working schema's is installed on a VirtualBox virtual machine running Oracle Enterprise Linux 6.4. The VM is configured to use Network Address Translation (NAT). This means the VM box can be accessed on IP adress 127.0.0.1 or localhost. To make sure that the database connections are actually sent to the VM, instead of the windows machine, we need to configure Port Forwarding. This had been setup for the database listener (port 1521) and the ODI agent running on port 15101. What I had omitted to do was add port forwarding for the JMXPort used for debugging. Adding port 16101 solved the problem.