I don't know wether it's a typo or not but you are missing a ; on the first commented line. You may also want to look at using $return to get data out of the productions rather than modifying global vars. Something like this may work

file: hdr body ftr
{
   $return = {hdr => $item{hdr},
              body => $item{body},
             };
}
body: batch(s)
hdr: /^HDR.*\\n/
ftr: /^FTR.*\\n/
batch: bathdr tran(s) batftr
{
   $return = {bathdr => $item{bathdr},
              tran => $item{"tran(s)"},
             };
}
bathdr: /^BHD.*\\n/
{
   $return = substr($item[1], 30, 3);
}
batftr : /^BFT.*\\n/
tran: TR1 TR2
{
   $return = {%{$item{TR1}},
              %{$item{TR2}},
             };
}
TR1: /^TR1.*\\n/
{
  $return = { str4 => substr($item[1], 35, 8),
              str2 => substr($item[1], 122, 5),
            };
}
TR2: /^TR2.*\\n/
{
   $return = {str3 => substr($item[1], 103,2)};
}
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the return from the parser will be the datastructure you created and you can then print/manipulate it outside of the parser. Not tested at all.