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 Making the Static Library Making xor.o Making xor Making sin.o Making sin Making letters.o Making letters Making four.o Making four Making walker.o Making d_walker.o Making bwin.o Making nwin.o Making d_walker.a Making walker Making grid_w.o Making d_grid_w.o Making d_grid_w.a Making grid_w Removing local object/library files. Removing local object/library files. Installing two examples. The others work better from the apps dir. Be root you fool. make[1]: *** [install] Error 1 make: *** [install] 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.