Hi Pietro,
I have launched two uploads with GWtoolset but it looks like the process
has stopped after 5-6 records: did anyone have this problem before?
Since recently the GWToolset logs its actions in < https://commons.wikimedia.org/wiki/Special:Log/gwtoolset%3E. Apparently there was a 404 issue with some of your files − that may be related?
Hope that helps,