$File_Name = Get_File_Name(param('filename'));

sub Get_File_Name{
    if($ENV{HTTP_USER_AGENT} =~ /win/i){ 
        fileparse_set_fstype("MSDOS");  
    } 
    elsif($ENV{HTTP_USER_AGENT} =~ /mac/i) {
        fileparse_set_fstype("MacOS");
    }
    my $full_name =  shift;
    $full_name    =  basename($full_name);
    $full_name    =~ s!\s!\_!g;          # Replace whitespace with _
    return($full_name);
}

storeFiles($File_Name, $Directory);

sub storeFiles{
  my($filename, $directory) = @_; #name subroutine variables
    my $data;
    my $mime = uploadInfo($filename)->{'Content-Type'};
    open (STORAGE, ">$directory/$filename") or die "Error: $directory/
+$filename: $!\n";
    if($mime !~ /text/){
        binmode ($filename);
        binmode (STORAGE);
    }
    while( read($filename, $data, 1024) ){ print STORAGE $data;}
    close STORAGE;
}
[download]

So I'm getting $File_Name using calling $Get_File_Name with param() and getting $filename in the subroutine with my($filename, $directory) = @_; #name subroutine variables. I will readily admit I don't understand the @_ very much. I printed both variables to see what they were and they both had the same value (a filename: test_file.doc), which is what I'd expect.