The insert did not create a real result we can work with

Hi. I am still trying to get my appointments + plugin to talk to my google calendar. At last I can make a "test" appointment. What is not happening though is that my website (scenarworks.net) , when a visitor wants to make an appointment, the calendars shown do not show the appointments already in gcal.

When I look at the log i get the following error:
"The insert did not create a real result we can work with"
What am I doing wrong??

With many thanks in anticipation.

Vincent Bowyer