Your Makefile looks fine, but it is hard to debug this visually. You are doing this in Eclipse? Open up a Cygwin terminal and type "make". You should see a line like:
g++ game.cpp Manager.o LogManager.o -o game -lncurses -lrt
If you do not, something is wrong with your Makefile. If you do, it should report an error that is more descriptive than "Error 1".