This happens whenever a simulation tries to run on a computer where the software has not been properly installed. It can be resolved in the following way:
Copy ‘lvrt.dll’ (normally located in c:\program files\virtual physical laboratory) and ‘lvsound.dll’ (normally located in c:\program files\virtual physical laboratory\sound\data) into the folder containing the simulation that will not run. Note they they should be copied (not cut & pasted or dragged).
