I believe that's actually the error message coming from the camera. We had 1 other Foscam user report this issue in the past but we ultimately didn't hear back from him on a request to get some more information to try to fix it.
Immediately after getting the error, please user "Report Bug" from the home settings, and check the checkboxes to include logs from BOTH your browser and your Camect device.
Also, if you want to get your camera working soon, try adding it manually ... home settings > devices > add camera, then set the type to "Stream URL" and use the url
rtsp://USERNAME:PASSWORD@IPADDRESS:88/videoMain
(Let us know if the manual add works.)