WARNING: XML ERROR (23): EntityRef: expecting ';'

Dear All.
First: thank the authors of BackWPup for the plugin.
Then:
I’m getting this error WARNING: XML ERROR (23): EntityRef: expecting ‘;’
and I’ve searched and searched for an answer and I didn’t find no working solution.

I’ve deleted the plugin, deleted the job,… all from scratch and no good!
Please can you give some orientation on this?

I have this log:

[10-Sep-2014 15:35:21] 1. Trying to create a WordPress export to XML file …
[10-Sep-2014 15:35:22] Check WP Export file …
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] WARNING: XML ERROR (23): EntityRef: expecting ';'
[10-Sep-2014 15:35:22] Added XML export "website.wordpress.2014-09-10.xml" with 650.69 kB to backup file list.
[10-Sep-2014 15:35:22] 1. Trying to generate a file with installed plugin names …
[10-Sep-2014 15:35:22] Added plugin list file "website.pluginlist.2014-09-10.txt" with 2.17 kB to backup file list.
[10-Sep-2014 15:35:22] 1. Trying to generate a manifest file …
[10-Sep-2014 15:35:22] Added manifest.json file with 5.91 kB to backup file list.
[10-Sep-2014 15:35:22] 1. Trying to create backup archive …
[10-Sep-2014 15:35:22] Compressing files as ZipArchive. Please be patient, this may take a moment.

Thank you all.
AMP
https://www.ads-software.com/plugins/backwpup/