BackupMonitor: important bugfix

A nasty bug found its way in the latest release of BackupMonitor which caused the program to suddenly exit when something went wrong during the execution of one of the backup script. The bug has been corrected  (a problem with threads and a method call that should have been asynchronous) and the "correct" behaviour is back: when something goes wrong an error log is displayed and the program "hiberantes" until the user wakes it up. The updated version can be downloaded from the project's page.