Thanks for sending maxout.gnuplot_pipes.
When I run gnuplot (4.7 from cvs) it successfully plots the data.
So it's hard to figure out what's going on.
One idea: can you run Gnuplot within gdb (debugger).
If the installed binary has been stripped of symbols,
try running the one from the build directory. e.g.
$ cd <whatever>/gnuplot
$ gdb src/gnuplot
<now try the offending data file>
When Gnuplot seems to wait forever, hit control-C
and then enter the command "where" in gdb.
It should give you a stack trace.
best
Robert Dodier