checking your g++. checking your flex. checking your libjneural. You're going to need libjneural to pull this off. Fortunately, I can help you out. tar -xf jneural*.tar cd jneural; ./configure --prefix=/usr/local; make && make install creating cache ./config.cache checking for gcc... gcc checking whether the C compiler (gcc ) works... yes checking whether the C compiler (gcc ) is a cross-compiler... no checking whether we are using GNU C... yes checking whether gcc accepts -g... yes checking how to run the C preprocessor... gcc -E checking for flex... flex checking for yywrap in -lfl... yes checking for a BSD compatible install... /usr/bin/install -c checking whether make sets ${MAKE}... yes checking for bison... bison -y checking for main in -lncurses... yes checking for main in -lfl... yes checking for main in -lm... yes checking for ANSI C header files... yes checking for unistd.h... yes checking for working const... yes checking for strstr... yes updating cache ./config.cache creating ./config.status creating Makefile creating apps/displays/Makefile creating apps/Makefile creating utils/Makefile creating nets/Makefile creating arch/Makefile creating docs/Makefile creating jneural.spec Making synaptic_group.o Making neuron.o Making layer.o Making hidden_layers.o Making sarsa.o Making backprop.o Making kohonen.o Yaccing matrix.y Making matrix.o Lexing matrix.l Making lex.yy.o Making io.o Making matrix_reader.o Making transfer.o Making real.o Making normalizer.o Making the Dynamic Library powerpc-apple-darwin8-gcc-4.0.1: unrecognized option '-shared' /usr/bin/ld: unknown flag: -soname collect2: ld returned 1 exit status make[1]: *** [libjneural.so_real] Error 1 make: *** [libjneural.so] Error 2 Died at Makefile.PL line 42. You're going to need libjneural to pull this off. However, soemthing went wrong with the installation. cleaning up some test files. creating a fake jNeural.c (there's no jNeural.xs _yet_). make: *** No targets specified and no makefile found. Stop.