#!/usr/bin/perl -w
use strict;

my $path = "C:/Program Files/Perl Express/example.txt";
#there is no need to "escape" the double quotes.
print "$path\n";
my $root = "C:/Program Files/Perl Express";
my $somefile = "X Y Z.dat";
my $somefile_path = "$root/$somefile";
print "$somefile_path\n";

__END__
prints:
C:/Program Files/Perl Express/example.txt
C:/Program Files/Perl Express/X Y Z.dat