The Qucs 0.0.19 version is a zip file with no setup installer!! I made mention of this in another ticket. I have now looked into the unzipped files that I used for the install. Specifically the attached batch file that creates the digi.exe file which the simulator cannot find. Looking at the attached batch file, it's been a long time since I've had to use DOS batch files, I noticed, that as far as I can determine, this will create the exe file that the simulator is complaining it can't find. So, as far as I can see, there must be an environment variable that needs to be fixed to get this thing running. I have seen the properties menu, but cannot, for the life of me, figure out what to do with these parameters. Of course a proper setup utility would be the fix for others to use this thing!