Thank you for your very kind and patient response. First let me establish
that the reason the google calendar wouldn’t import was my fault – I
grabbed the wrong url. Once i grabbed the correct URL, it went in correctly.
Here is the webcal url that the aggregator would not consume: webcal://
prmrocks.org/?plugin=all-in-one-event-calendar&controller=ai1ec_exporter_controller&action=export_events&no_html=true