plot2d discrete mode Bad Range error



Hello,

I am working my through the plotting chapter of the maxima reference manual (
http://maxima.sourceforge.net/docs/manual/en/maxima_8.html#SEC32 ) and I am
encountering a "Bad Range" error when I execute the plot2d function in discrete
mode.  An example maxima session that shows the error is included below.  Does
anyone have any thoughts on what I may be doing wrong?

Thanks in advance :-)

Ted

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tkosan at hpb ~ $ rmaxima 
Maxima 5.9.1 http://maxima.sourceforge.net
Using Lisp CMU Common Lisp CVS 19c 19c-release + minimal debian patches (19C)
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
This is a development version of Maxima. The function bug_report()
provides bug reporting information.
(%i1) xy:makelist([x,x*x],x,0,5)$

(%i2) xy;

(%o2)         [[0, 0], [1, 1], [2, 4], [3, 9], [4, 16], [5, 25]]
(%i3) plot2d([discrete,xy])$

Bad Range 
FALSE must be of the form [variable,min,max]
 -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);
(%i4) 
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