If you have problems getting the program to run on Windows the most common reason is the system path. The path should contain the gnuplot binary and the installation folder of the script (for reflectometry simulation the fortran compiler binary path needs to be there at a position before the other folders, too). If you can't run the program after installation, check the path variable in the advanced system settings (if you don't know where this is try google).
After an update through the repository the program starts with an error message and does not work any more. Try to remove the ~/.plotting_gui/config folder to resolve the issue.
path=C:\program files\plot-script\gfortran\bin;%path%
plot.exe %*