Let me just get this out of the way first: I love iCam. Your software rocks, and we feel much safer knowing we can log in and see our home while we're away.
Problem: Almost once a week, I get the "No Sources Found" error in the app. I call my wife at home, she unplugs the cameras from the wall and plugs them back in. Still no sources found. I use LogMeIn to connect to the iMac, open Foscam's IP tool, and paste the new local IP addresses (like 10.0.1.9:6001) into iCamSource. Then we're back in business for another 7 days or so.
Details:
iCamSource 2.4.8 on a late-2011 iMac w/ Lion
Airport Extreme
(2) Foscam FI8910W
Not sure if I'm missing a step here, or if I left out any details. Please let me know, and I will add them.