Please check your DriveHQ Online Backup version. Try to upgrade to the latest version. You can find the latest version at:
http://www.drivehq.com/downloads/downloads.aspx
The problem appears to be caused by missing PC-ID. When you create a backup task on a PC, the task is associated with this PC; if you go to another PC, create another backup task using the same source folder and the same task name, the new task is associated with the new PC. This prevents data being overwritten due to multiple PC backup.
When you logon the first PC, you can only edit and manage backup tasks created on this PC. You cannot edit / manage tasks created on other PCs. This is as design.
In your case, it seems DriveHQ Online Backup believes the backup task(s) was created on a different PC. To resolve the problem, you need to delete the backup task and re-create it. When deleting the backup task, please don't delete the backup sets on Server. This way, you can re-create the same backup task (using the same source folders and the same task name). DriveHQ Online Backup will automatically skip uploading the same files again.