If you look at this

    #!/usr/local/bin/math8.0.4/MathematicaScript -script
    
    $HistoryLength=0;
    $pwf=FileNameJoin[{NotebookDirectory[],FileBaseName[NotebookFileName[]]}];
    $pwf = "test";
    $parameterfile=StringJoin[$pwf,".dat"];
    Print[$pwf];
    Print[$parameterfile];


you will see that both Print statements work just fine - What requires the FrontEnd are the `Notebook*XY*[]` functions and since this is a script and not a notebook these are not avaiable. So you'd need to replace those. You could, for example use `$InputFileName` and derive the information from that instead.