Source code is originaly compiled with ASEM 51 (http://plit.de/asem-51/) Check if asem51 is correctly installed and binaries are in the system path.
just type "make" to build the source
Make sure asem51 binaries are in the system path, if not, you can also copy asem.exe, hexbin.exe and 83c552.mcu in the "src" directory beware of the length of files & directories names ("8.3" DOS names must be used
the root of the drive would be a good choice as the main directory).
Run "build.bat"
(Without make or build.bat)
Don't forget to add the TARGET and FREQ constants in the command line.
i.e : "asem -d TARGET:8060 -d FREQ:144 prm.a51"