Using Google Base Feeder 1.8.2
Zen 1.3.9h

When producing a google base feed file. If I set the Include Quantity Zero to true. I get an output file with this error

XML Parsing Error: mismatched tag. Expected: </title>.
Location: file:///C:/Store/mystore_products.xml
Line Number 262, Column 34:<g: product_type><![CDATA[DVD]]> /g: product_type>
---------------------------------^

Google picked up on it too and advised me of the error.
Now if I turn Include Quantity Zero to false the file is fine and google processes it fine.

Why does this happen and how can I fix it?