CoursePress Pro plugin calendar widget not working + Theme choice

Hello!

I am looking at the Coursepress Pro plugin widget 'course calendar' and have tried to add it in the sidebar of the homepage with Coursepress Theme - nothing appears. However, if I use Twenty Twelve theme the calendar does appear in the sidebar, but is messed up (the numbers cluster to adjacent date numbers in an unreadable way). What is wrong here and how can it be fixed?

Moreover, can I use a different theme for Coursepress Pro plugin and which themes will work well with this plugin?