said by LittleBill:you also need to open a port range for the passive ports, since the client is trying to use passive connect, you then need to to go into the server options and add those ports into the passive range you extended
other wise has to be configured to use active and not passive
That was the problem - I had to open a series of ports for Passive mode and set them statically in the server interface in addition to specifying my external IP address. I wonder why the first two files would transfer though?