Are you trying to use the shift key to select multiple items? That is supported and works on my test system here.
Or are you trying to use the shift key to change the drag process from copy to move? That is not supported.
If you ever get unexpected results, the most helpful thing to do is to save the trace file and email it to me. You can save a trace file using the FlashScan menu option: F2 Scan Tool -> F3 Scan Options -> F1 Save Trace File.
Is "VPW xx" (where xx is 02 or higher) displayed in the lower right corner of FlashScan's screen? The 02 means FlashScan has found at least 2 modules - ECM and TCM.
If not, please press Ctrl+OK to re-detect the protocol and modules in the vehicle.
Also, please save and send a trace file after that error.
Regards
Paul