Plesk 12.xx schedulled backup hangs at 100%

Hello,

I have an issue with my daily backup.
I configured to have a daily backup on an external FTP server. Everything looks to work correctly but in the panel I see that the task is a 100% forever. Never finisihing completly.. So the next day, the task is not starting.. I have to remove manually the task in backup manager screen.

here is the last lines of the log file (in /var/log/plesk/PMM/backup-2015-01-20-20-46-02-824)

[2015-01-20 21:33:53.108|18485] INFO: ENV[LANG]=en_US.UTF-8...

Plesk 12.xx schedulled backup hangs at 100%