While doing the operation in KMC, run:
# kaltlog
from the server's shell and look at the errors.
Also, if you are using Red5 for recording, try re-running:
# kaltura-red5-config.sh
My first guess would be a permissions issue on $BASE_DIR/web/content/webcam or a missing symlink:
ln -sf /usr/lib/red5/webapps/oflaDemo/streams $BASE_DIR/web/content/webcam
if the issue is either, rerunning the config script should fix it.