Description:
------------
Looks like there may a bug in the PHP Intl code, after I downloaded and tested  PHP 5.5.5-1+debphp.org~raring+1, and PHP Intl PECL-3.0.0 with ICU 52.1.

Test script:
---------------
<?php
if (!extension_loaded('intl'))
   die('skip intl extension not enabled');
ini_set("intl.error_level", E_WARNING);
ini_set("intl.default_locale", "lo_LA");
echo INTL_ICU_VERSION;
$bi = IntlBreakIterator::createWordInstance('lo');
$myText =
"ພຣະທັມເຮັບເລີຄາດຄະເນລ່ວງໜ້າວ່າຄົນຈະຮູ້ແລະເຂົ້າໃຈເຖິງວຽກງານຂອງປະໂລຫິດໃນສະໄໝຂອງຊົນຊາດອິດສະລາເອນເພື່ອວ່າຜູ້ທີ່ຮັບຈົດໝາຍທີ່ຖືກບັນທຶກໄວ້ໃນພຣະທັມນີ້ຈະສາມາດເຂົ້າໃຈວ່າພຣະເຢຊູຊົງເຮັດສິ່ງໃດສຳລັບພວກເຂົາໃນສະຫວັນ";
$bi->setText($myText);
var_dump($bi->first());
var_dump($bi->next());
var_dump($bi->next());
var_dump($bi->next());
var_dump($bi->next());
var_dump($bi->next());
var_dump($bi->next());
?>

Expected result:
----------------
PHP Output:
52.1
int 0
[... a few int #'s starting from 0 to 597 ...]
int 597

Actual result:
--------------
PHP Output:
52.1
int 0
int 597
int -1
int -1
int -1
int -1
int -1