my $base = 'D:\Some\Specific\Folder\Archive\\';
# should be:
my $base = 'D:/Some/Specific/Folder/Archive'; # a path to a directory
or
my $base = "D:/Some/Specific/Folder/Archive"; # a path to a directory
# do not put a trailing '/' or '\' on a directory name
# this is not needed and can confuse the shell
# pre-pend a '/' when you expand the path
my $new = "$base/$extra_path";