Thanks, TLS - that looks like an elegant and (very) cheap fix. Do you think that part would be available on the shelf at an electronics store or is it one of those obscure pieces that I will have to order off the website?
And Mark, you are more than likely correct about my friend being an idiot - he hooked it up back in college and didn't really have any specialized knowledge. I think I can post pictures now, so here's how he had it - if we number the speaker inputs 1-8 starting in the top left corner, he had one speaker hooked into 1 and 3 and one hooked into 6 and 8.
Now, you are telling me to use 1,2 and 7,8, while another person is telling me to stay in channel A and use 1,2 and 3,4. I suppose none of it matters as I will be using the adapter, but just for my own edification - what did my friend do originally? He claimed he was "bridging" the amp. Something about halving the ohms and doubling the power....I'm not sure, it was a while ago.
Also, if someone could explain the significance of the impedance selector above the speaker inputs that would be great. I have it set to the left at the moment (A or B, 8 ohms min per speaker), though abovementioned idiot had it to the right (A or B 4 ohms min per speaker/A+B 8 ohms min per speaker).