From your first post, it sounds like you've attempted to use icamsource with and without the "auto config router" setting enabled and still experience the same issue. Is that correct? If you haven't tried it both ways, try running icamsource with the "auto config router" disabled. In my experience, it works best in that configuration when only using 1 camera.
If that doesn't work, and the "auto config router" option didn't work, then I'm out of ideas (unless your DSL modem has a built-in firewall...in which case you'd need to enable uPNP on the router OR set up manual port forwarding in both the router AND in icamsource). If you're not sure, you can post the brand/model of your DSL modem and I'll try to find out for you.
If there's anything I'm missing, I'm sure the SKJM guys will jump in.