Hi Mikey, I have the mk1 version of the aego p5's, they're great, it's hard to believe how much power and how good the quality is of these little speakers
I only actually use the optical input at the moment, from my HTPC, but I have used line inputs before and didn't have any problems.
Have you checked the settings on the LCD, are you sure these are actually line output sockets? do they need to be enabled?
One of my mates had a similar problem and had to use the headphone output to his amps line input by using an adapter cable.