Do you see the Source Connection Error when your iPhone is connected to 3G, local Wi-Fi, or both?
Also, what are your computer's specs (CPU speed, RAM, etc.)? An older Mac might not be able to handle three instances of iCamSource at the same time. The motion detection processing adds significantly to the CPU usage, so it may be necessary to dial that down if you're using an older Mac. To do so, simply copy and paste the following line of text to an Applications > Utilities > Terminal window and hit Return:
defaults write com.skjm.icamsource MotionDetectionWait -int 5000
The number at the end is the number of milliseconds that the iCamSource will wait before checking for motion. You have to restart the iCamSource for any change you make to have an affect.