I was getting this error as well. I was running the 0.7.3 version & upgraded to 2.1 b/c I thought it would fix. It did not. I reentered my feed address which cleared a 403 error. But not the parsing error. I tried checking the “use the simple display options” setting on the feed — didn’t help either. Finally I pasted the customized code I had set in the old version of the code for the list events to display & it worked. Granted it still is not displaying all day events.
But try editing the code that displays the feed.