When it happens, is dopus.exe listed as a running process in Task Manager (click More Details, then the Details tab)?
If it is there, please right-click it, then choose Create Dump File from the context menu. This will create a .dmp file in the temporary folder (a dialog will show you the actual filename once it's been created).
If you can zip that .dmp file and email it to leo@gpsoft.com.au (or if it's too big for email, put it on a file sharing site like OneDrive or Google Drive and email us a link) we can hopefully find out from that what's happening.