Hello from Spain. I installed Guile 2.0.3 and it works well. I've tried Tortoise tutorial: http://www.gnu.org/software/guile/docs/guile-tut/tutorial.html and it compiled well, Gnuplot window pops up, but (tortoise-move 3) doesn't draw. The source code is:

/* Simple backend for a Logo like tortoise drawer. */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <math.h>
#include <libguile.h>

static const int WIDTH = 10;
static const int HEIGHT = 10;
static FILE* global_output;
static double x = 0.0;
static double y = 0.0;
static double direction = 0.0;
static int pendown = 1;

static FILE* start_gnuplot ();
static void draw_line (FILE* output, double x1, double y1, double x2, double y2);
static SCM tortoise_reset ();
static SCM tortoise_pendown ();
static SCM tortoise_penup ();
static SCM tortoise_turn (SCM degrees);
static SCM tortoise_move (SCM length);
static void* register_functions (void* data);

static FILE* start_gnuplot ()
{
FILE* output;
int pipes[2];
pid_t pid;

pipe (pipes);
pid = fork ();

if (!pid)http://www.gnu.org/software/guile/docs/guile-tut/tutorial.html
    {
      dup2 (pipes[0], STDIN_FILENO);
      execlp ("gnuplot", NULL);
      return; /* Not reached. */
    }

output = fdopen (pipes[1], "w");

fprintf (output, "set multiplot\n");
fprintf (output, "set parametric\n");
fprintf (output, "set xrange [-%d:%d]\n", WIDTH, WIDTH);
fprintf (output, "set yrange [-%d:%d]\n", HEIGHT, HEIGHT);
fprintf (output, "set size ratio -1\n");
fprintf (output, "unset xtics\n");
fprintf (output, "unset ytics\n");
fflush (output);

return output;
}

int main (int argc, char* argv[])
{
global_output = start_gnuplot ();

scm_with_guile (&register_functions, NULL);
scm_shell (argc, argv);

return EXIT_SUCCESS;
}

static void draw_line (FILE* output, double x1, double y1, double x2, double y2)
{
fprintf (output, "plot [0:1] %f + %f * t, %f + %f * t notitle\n",
           x1, x2 - x1, y1, y2 - y1);
fflush (output);
}

static SCM tortoise_reset ()
{
x = y = 0.0;
direction = 0.0;
pendown = 1;

fprintf (global_output, "clear\n");
fflush (global_output);

return SCM_UNSPECIFIED;
}

static SCM tortoise_pendown ()
{
SCM result = scm_from_bool (pendown);
pendown = 1;
return result;
}

static SCM tortoise_penup ()
{
SCM result = scm_from_bool (pendown);
pendown = 0;
return result;
}

static SCM tortoise_turn (SCM degrees)
{
const double value = scm_to_double (degrees);
direction += M_PI / 180.0 * value;
return scm_from_double (direction * 180.0 / M_PI);
}

static SCM tortoise_move (SCM length)
{
const double value = scm_to_double (length);
double newX, newY;

newX = x + value * cos (direction);
newY = y + value * sin (direction);

if (pendown)
    draw_line (global_output, x, y, newX, newY);

x = newX;
y = newY;

return scm_list_2 (scm_from_double (x), scm_from_double (y));
}

static void* register_functions (void* data)
{
scm_c_define_gsubr ("tortoise-reset", 0, 0, 0, &tortoise_reset);
scm_c_define_gsubr ("tortoise-penup", 0, 0, 0, &tortoise_penup);
scm_c_define_gsubr ("tortoise-pendown", 0, 0, 0, &tortoise_pendown);
scm_c_define_gsubr ("tortoise-turn", 1, 0, 0, &tortoise_turn);
scm_c_define_gsubr ("tortoise-move", 1, 0, 0, &tortoise_move);
return NULL;
}

What's wrong ?