I finally managed to get this server operating. While playing around I set the "force networking on interface" to "en0" in the "general configuration"-tab. But, as it is in real life, you'll never run out of problems. Right now, the ps3 can only see my internal harddrive on my imac, but none of the hard drives connected to the imac via usb.
Any clues, what's wrong?
Anyway, I could actually use the app for a while and I must say: This is by far the best ps3 media server I ever came across!
Playing hd-mkvs or video_ts folders is just a breeze. Finally someone found a way to help the playstation to become, what it should have been right from the beginning: a true media player, and definitely not a game console!
A big thank you to the developers, what a great application that is!
By the way, after your total reset of your imac, do you see attached hard drives through the ps3?