Code showing up on web page

Hi,

So far I am excited about this plug in because I was finally able to create a short code for future events. I’ve tried so many other plug-ins that simply would not work even when they specifically said this was their purpose.

That said, I’m having a weird problem creating a shortcode to list posts from a specific post category. It works, but it also shows code jumbled onto the final output on the webpage:

http://www.melanieinmiami.com/under-construction-in-miami/brickell-city-centre/

What am I doing wrong, and how can I fix it? Thanks!