Yes, you are right. The error is this:

pp2@europa:~/LGRID-Machine/examples/matrixproduct/open2$ ./matrix_grid
+.pl
Can't open perl script "/tmp/gridmachine_driver_matrixZNJuj": No such 
+file or directory
Use of uninitialized value in eval "string" at ./matrix_grid.pl line 1
+88, <GEN16> chunk 171.
Use of uninitialized value in eval "string" at ./matrix_grid.pl line 1
+88, <GEN16> chunk 171.
Use of uninitialized value in eval "string" at ./matrix_grid.pl line 1
+88, <GEN16> chunk 171.
Wrong result from process 0 in machine bw
pp2@europa:~/LGRID-Machine/examples/matrixproduct/open2$ Can't open pe
+rl script "/tmp/gridmachine_driver_matrixj64e3": No existe el fichero
+ o el directorio

pp2@europa:~/LGRID-Machine/examples/matrixproduct/open2$
[download]

If I uncomment the sleep in

pp2@europa:~/LGRID-Machine/examples/matrixproduct/open2$ sed -ne '153,
+168p' matrix_grid.pl
foreach (@str_handles) {
  my $pid = $pm->start and next;

  $b = syswrite $_->{handle},
           join(" ",
                  $_->{chunksize},
                  $_->{A_cols},
                  @A_lines[$_->{start}.. $_->{end}],
                  @B_lines,
                  "\cN"
               );
  # Wait until the writing has finished
  # sleep(1);
  $pm->finish;
}
[download]

It goes OK:

pp2@europa:~/LGRID-Machine/examples/matrixproduct/open2$ ./matrix_grid
+.pl
Process 0: machine = bw received result
Process 1: machine = beowulf received result
Process 2: machine = europa received result
Process 3: machine = orion received result
Elapsed Time: 1.148361 seconds
[download]

I know is still very cryptic. Apologies.

Casiano