error with my octave installation?

[Peter Hinow]

Hello all,
as I'm totally new to octave, I don't know yet how to report a problem or how 
to diagnose one. I did not install octave 3.0.1 explicitly, it came with the 
installation of Ubuntu 9.04 from a live CD. Then I encountered a problem using 
the pdist.m function. I got pdist.m and squareform.m from 
http://octave.sourceforge.net/doc/funref_statistics.html

The following set of commands works just fine
a=rand(257,3);
d1=squareform(pdist(a,"euclidean"));
However, increasing the size of the data by one
a=rand(258,3);
d1=squareform(pdist(a,"euclidean"));
gives a large number of error messages that are all

error: called from `nchoosek' in file 
`/usr/share/octave/3.0.1/m/specfun/nchoosek.m'
error: evaluating assignment expression near line 79, column 7
error: evaluating if command near line 69, column 3

How do I check whether my octave installation is correct?
Thank you and best regards,
Peter