The 'aMule TCP/UDP Port Connection Tester' actually only tests TCP ports which is the reason I found out that it always reports the following for port 4672:
Error: TCP port 4672 is unavailable. Make sure your firewall or router is allowing/forwarding this TCP service port and your ED2K client is running (i.e. aMule, eMule).
Detailed Error Message
TCP Error 110 Connection refused
Because port 4672 is NOT a TCP port, but a UDP port. I'm told eMule can directly check UDP ports, but obviously aMule is not as feature rich so how do I check if port 4672 is open? I'm getting high ID as signified by the green arrow, but my downloads are painfully painfully slow even though I have only 'verified' servers. At present I have only two files to share so could that be the reason for the always slow downloading and low clients on queue? Originally I had dozens of huge files to share, but all were lost in a HD crash and so I've had to start from scratch, still I think there could be some problem with UDP port 4672.