If ShipLinx freezes up and hangs and doesn't react when it's trying to pull the weight or Rate (sometimes you don't know specifically)...
Close ShipLinx from the Task Manager, re-open it, remove the Scale Device, and test to see if that stops the hang-up.
If this seems to be the case, have the client reset the Scale and the retest it (you don't need to restart ShipLinx to do so).