I've reported this problem to DriveHQ support twice over the past few weeks since I subscribed, and have received no response. This seems to be a good product, but if they're not going to respond to customers I'll have to look elsewhere.
FileManager does not recover from hibernate or suspend when the system wakes up. If a sync was in progress it is stopped, and data transfer doesn't work properly when the "resume" button is hit. The only way I've found to recover is to exit the entire application from the system tray, and restart DriveHQ from scratch.
The system will also recover if it is rebooted, but the backlog of data can be very large if you don't do this regularly.