by Ken Task.
Don't run Windows ... but ...
It does say time out exceeded - 3600!!! That's a lot! How large is the .mbz file?
The sometimes thing could be related to cron job/task that kicks in to clean up moodledata/temp/backup/ where moodle extracts the .mbz to restore to site.
Since you can use command line, look in code/admin/cli/ for a php script called backup. Run from command line have to give it the course id number and destination ... where you want the backup to go.
There is also in version 4 a restore_backup.php script. I've never used it so can speak from first hand experience because I use Linux and use moosh for that sort of CLI job.
'SoS', Ken