This version of pst-barcode uses the xkeyval package, the extended version of keyval.

Save the files pst-barcode.sty|.tex|.pro in a directory, which is part of your local TeX tree. pst-barcode.pro should be saved in ../texmf/dvips/pstricks/ Then do not forget to run texhash to update this tree. pst-barcode needs pstricks, which should be part of your local TeX installation, otherwise get it from a CTAN server, f.ex. http://mirror.ctan.org/graphics/pstricks/