line 24 - remove double " 
#open my $fileone, '<', "$folder/$file" or die ""$folder/$file": $!";
##</code><code>##

die "'$folder/$file': $!";    # choose a different literal character
die "\"$folder/$file\": $!";  # escape the inner "
die qq{"$folder/$file": $!};  # use an alternative outer delimiter