Here is the thread I'm talking about. 4th from the bottom Miguel Frade says that upgrading from php 5.3.10 to 5.4.17 solved his problem with proc_open().

As for me, I turned on CAS, debugging, and ran the CAS command directly on maxima command prompt. It seems OK to me. But expert advice is welcome.

(%i1) load(".../moodledata/stack/maximalocal.mac");

Loading maxima-grobner $Revision: 1.6 $ $Date: 2009-06-02 07:49:49 $

WARNING: DEFUN/DEFMACRO: redefining function TEX-MQUOTIENT in .../edukone/question/type/stack/stack/maxima/stacktex.lisp, was

defined in /.../tmp/maxima-5.31.3/src/binary-clisp/mactex.fas

WARNING: DEFUN/DEFMACRO: redefining function TEX-MATRIX in .../edukone/question/type/stack/stack/maxima/stacktex.lisp, was defined

in /.../tmp/maxima-5.31.3/src/binary-clisp/mactex.fas

WARNING: DEFUN/DEFMACRO: redefining function TEX-PREFIX in .../edukone/question/type/stack/stack/maxima/stacktex.lisp, was defined

in /.../tmp/maxima-5.31.3/src/binary-clisp/mactex.fas

WARNING: DEFUN/DEFMACRO: redefining function TEX-STRING in .../edukone/question/type/stack/stack/maxima/stacktex.lisp, was defined

in /.../tmp/maxima-5.31.3/src/binary-clisp/mactex.fas

WARNING: DEFUN/DEFMACRO: redefining function TEX-DERIVATIVE in .../edukone/question/type/stack/stack/maxima/stacktex.lisp, was

defined in /.../tmp/maxima-5.31.3/src/binary-clisp/mactex.fas

WARNING: DEFUN/DEFMACRO: redefining function TEX-D in .../edukone/question/type/stack/stack/maxima/stacktex.lisp, was defined in

/.../tmp/maxima-5.31.3/src/binary-clisp/mactex.fas

WARNING: (SETF FIND-CLASS): redefining class MRING in /.../usr/local/share/maxima/5.31.3/share/linearalgebra/mring.lisp, was defined in

/.../tmp/maxima-5.31.3/src/binary-clisp/numth.fas

0 errors, 1 warning

[ STACK-Maxima started, library version 2013060300 ]

(%o0) ".../moodledata/stack/maximalocal.mac"

(%i1) cab:block([ RANDOM_SEED, OPT_NoFloats, sqrtdispflag, simp, assume_pos, caschat0, caschat1], stack_randseed(0), make_multsgn("dot"), make_complexJ("i"), make_arccos("cos-1"), OPT_NoFloats:true, sqrtdispflag:true, simp:true, assume_pos:false, print("[TimeStamp= [ 0 ], Locals= [ ") , print("-1=[ error= ["), cte("__stackmaximaversion",errcatch(__stackmaximaversion:stackmaximaversion)) , print("0=[ error= ["), cte("caschat0",errcatch(caschat0:plot([x^4/(1+x^4),diff(x^4/(1+x^4),x)],[x,-3,3]))) , print("1=[ error= ["), cte("caschat1",errcatch(caschat1:plot([sin(x),x,x^2,x^3],[x,-3,3],[y,-3,3]))) , print("] ]") , return(true) );

[TimeStamp= [ 0 ], Locals= [

-1=[ error= [

], key= [

__stackmaximaversion

]

, value= [

2013060300

], display= [

2013060300

]

],

0=[ error= [

], key= [

caschat0

]

, value= [

" <html><div class=\"stack_plot\"><img src='!ploturl!stackplot-3596556655-57136044.png' alt='STACK auto-generated plot of [x^4/(x^4+1),4*x^3/(x^4+1)-4*x^7/(x^4+1)^2] with parameters x,-3,3' /></div></html> "

], display= [

\mbox{ <html><div class="stack\_plot"><img src='!ploturl!stackplot-3596556655-57136044.png' alt='STACK auto-generated plot of [x^4/(x^4+1),4*x^3/(x^4+1)-4*x^7/(x^4+1)^2] with parameters x,-3,3' /></div></html> }

]

],

1=[ error= [

plot2d: some values were clipped.

plot2d: some values were clipped.

], key= [

caschat1

]

, value= [

" <html><div class=\"stack_plot\"><img src='!ploturl!stackplot-3596556659-46248239.png' alt='STACK auto-generated plot of [sin(x),x,x^2,x^3] with parameters x,-3,3],[y,-3,3' /></div></html> "

], display= [

\mbox{ <html><div class="stack\_plot"><img src='!ploturl!stackplot-3596556659-46248239.png' alt='STACK auto-generated plot of [sin(x),x,x^2,x^3] with parameters x,-3,3],[y,-3,3' /></div></html> }

]

],

] ]

(%o1) true

(%i2)

I reviewing the clips installation as sometimes I get lisp errors.