I don't think the spaces in the name is the problem. I have several calendars which use spaces in their name. And if you use the new "Google Calendar (v3)" it doesn't even use the calendar name for identification.
Can you run Rainlendar in the debug
mode and create a calendar which shows the problem? Disable all your existing calendars before that so that the debug log doesn't contain any unnecessary information. Please send the log to Rainlendar's support email address with a link to this thread and I'll take a look at it.