Coursepress theme gives XML Parsing error

My Coursepress Pro theme gives an XML parse error - undefined entity when I try to access a URL: https://MySite.org/modules/MyCourse/units/
It seems to suggest something is wrong in this feed (which does not seem to be the case):
<link rel="alternate" type="application/rss+xml" title="MySite Title &raquo; Feed" href="https://MySite.org/feed/" />
The Twentytwelve theme works fine.
Suggestions?