Error in zip file

Hello, Whenever I open a zip file compressed by Xerte I get an error. It's not a show stopper as the zip is still usable, but it means I have to unzip and rezip for distribution.
The error is on the following file:
testing: common_html5/mediaelement/DO NOT CHANGE THESE FILES. USE -src- FOLDER.txt
error: invalid compressed data to inflate
thanks!