OK, I'm a bit stumped. RMS has had me up half the night pissing around with settings.
So, the instructions say to change IP addresses in the files as follows - does it really mean literally 10.10.10.10 or my actual server IP?:
path_to_rms/webapps/widget_name/WEB-INF/red5-web.properties
from
webapp.virtualHosts=0.0.0.0
to:
webapp.virtualHosts=10.10.10.10