ubuntu soundsc and fourier transform

[jordi lendinez]

Hi,

I was trying to use the function soundsc or sounds in octave, but I recives this message:

octave:5> y=randn(1,1000);

octave:6> soundsc (y)

error: portaudio not found on your system and thus audio functionality is not present

error: called from

audioplayer at line 105 column 19

soundsc at line 90 column 8

Too I was trying to use the fourier function like this: 

syms t w
fourier(t^3, t, w)

ans =
-pi*dirac(3, w)*2i

but that I recived is :

octave:6> syms t w
octave:7> fourier(t^3, t, w)
ans = (sym) 0

How I can solve this?

Thank you,

Jordi

P.D.: I attached a PDF with the input and output that I have and the link:
http://es.mathworks.com/help/symbolic/fourier.html
where I found the fourier function.

print_octave.pdf
Description: Adobe PDF document