I know this post is a month after, and maybe you already got your answer:
Okay, you have a standalone XML document.
And the contained text in the summary element has an '&' character.
Since '&' is understood in the XML doctype to indicate an entity reference, if you want the '&' character, you must use its character entity reference: '&' (without the quotes) to make it a valid XML document.
The same for the '<' and '>' characters: '<' and '>' respectively. Else the parser stops.