george.firefalcon on "WordPress's Export Posts Function and Plugin"

Good Afternoon, people.

I'm starting a new WordPress site (using all knowledge I gathered with my first), although I can't export my older WordPress's site posts through the Import/Export Plugin.

The xml archive is downloaded, but it displays an error, as below:
Error on XML processing: Prefix not associated to a namespace
Position: file:///.../firefalcon039sworld.wordpress.2016-07-27.xml
Line number 127, column 2

And the beginning of the line and column is shown as below:
<itunes:summary>Show me Your World</itunes:summary>
--------^

I'm not experienced as PHP Developer and WordPress developer, so I ask for your help. Thanks!