use strict;
use warnings;

my @results = do
{
		local $/ = ''; # paragraph mode
		map { my $p=$_; [ map { $p=~/$_ (\S+)/?$1:'UNDEF' } qw/TYPE CAUSE AFFECT/ ] } grep { /TYPE/ } <DATA>;
};
print "@$_\n" for @results;

__DATA__
// HEADER TAG
// VERSION TAG

TYPE VALUE1 EQUALS MAIN
I am useless text
CAUSE FAIL
AFFECT ERROR
ENDTYPE

TYPE VALUE2 EQUALS MAIN
I am useful test
ENDTYPE

TYPE VALUE3 EQUALS MAIN
CAUSE DEGRADED
ENDTYPE

TYPE VALUE4 EQUALS MAIN
AFFECT WARNING
ENDTYPE