Well folks, a very, very strange thing has happened.
Lately, I've been very busy at work, so I haven't had the time to mess around with aMule, the router or change ports. Every night, before leaving my Mac, I would log on to aMule, to see if there was any change, just in case.... you never know.
Well, tonight seems to be my lucky night! For some bizarre reason, I have High-ID... not that I'm complaining!
I was thinking of re-installing aMule, but in the end that wasn't necesary. However, I would be interested to find out what may have caused this problem, especially as I haven't touched anything.