How can I solve pmcov() error?

the function code is:

function [ Pxx ] = ARPMCOV (A,p )

    [H,F] = freqz(1,A,[],1); 
    plot(F,20*log10(abs(H)))

    xlabel('Frequency (Hz)')
    ylabel('PSD (dB/Hz)')

    rng default

    x = randn(1000,1);
    y = filter(1,A,x);
    [Pxx,F] = pmcov(y,p,1024,1);

    hold on
    plot(F,10*log10(Pxx))
    legend('True Power Spectral Density','pmcov PSD Estimate')
    end
  _____________________

Now, if I recall the function in the coomand window using for example: >> A=[-2 3 0,9 -1 2.3]; >> p=4; >> [ Pxx ] = ARPMCOV (A,p ) I have this errors: Error using arpest Expected X to be finite.

Error in arparest (line 38) validateattributes(x,{'numeric'},{'nonempty','finite','2d'},'arpest','X');

Error in armcov (line 37) [a,e,msg,msgobj] = arparest(x,p,'modified');

Error in arspectra (line 81) [a,v] = feval(method,x,p);

Error in pmcov (line 101) [Pxx,freq,msg,units,~,options,msgobj] = arspectra(method,x,p,varargin{:});

Error in ARPMCOV (line 15) [Pxx,F] = pmcov(y,p,1024,1);

thank you!