Problem with boxplot.m

[pedro]

Hi,

I am having trouble with boxplot.m:

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octave:216> boxplot([1, 2, 4, 5, 6, 7, 22, 33, 44])
error: __plt2__: invalid data for plotting
error: evaluating if command near line 48, column 3
error: called from `__plt2__' in file 
`/usr/share/octave/2.1.73/m/plot/__plt2__.m'
error: evaluating if command near line 58, column 4
error: evaluating if command near line 56, column 2
error: evaluating if command near line 55, column 7
error: evaluating while command near line 44, column 5
error: evaluating if command near line 30, column 3
error: called from `__plt__' in file 
`/usr/share/octave/2.1.73/m/plot/__plt__.m'
error: called from `plot' in file `/usr/share/octave/2.1.73/m/plot/plot.m'
error: evaluating if command near line 187, column 1
error: called from `boxplot' in file 
`/usr/share/octave/site/api-v13/m/octave2.1-forge/statistics/boxplot.m'

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Of course the call of boxplot is just an example. The example given 
under 'help boxplot' does not work either.
I use octave 2.1.73, boxplot.m is version 1.4.1.

Thanks for any help!

Best regards,
pedro.