Error loading afm character with pslib

[Antonio M]

I have a c example program of using pslib he compile fine but when I execute the program he say:

PSLib: Font outline could not be loaded for '/usr/share/texmf-texlive/fonts/afm/adobe/helvetic/phvb8a'.
PSLib: The font encoding vector does not contain the glyph 'onehalf'. Using '?' instead.
Segmentation fault

The line referred to the error is

fraktur = PS_findfont(psdoc,"/usr/share/texmf-texlive/fonts/afm/adobe/helvetic/phvb8a", "",1);
antiqua = PS_findfont(psdoc, "/usr/share/texmf-texlive/fonts/afm/adobe/helvetic/phvb8a", "" , 0);

The function don't find the encoding file and I don't now where is the enc file associate to that character