Maybe a simple state machine?

use strict;

my $in_section = 0;

foreach (<>) {
  $in_section=1, next if m{if\s+\(some\s+condition2\s+=\s+0\)}; 
  $in_section=0, next if m{^\s*end\s+if;}; # next could be omitted...h
+ere
  print if $in_section;
}

__END__
read this data 3;
read data 4;
read this data 6;
[download]

This one reads input from a list of files given by argument (@ARGV) when called as e.g. perl cond2reader.pl *.doc (or STDIN when no arguments were given). Alternatively, you can introduce an outer loop that opens all interesting files one after another (e.g. open my $fh, '<', $file or die "..."; foreach (<$fh>) { ... }
You might need to fine-tune the regular expressions a little bit.