weird string appears beside attribute selection in front-end

• I have zen cart 1.3.8 running on a local test site with WinXP and WAMP server (php v. 5.2.6 and mysql v. 4.1.22 and Apache 2.2.8). I have installed the Dual Pricing Module (v. 1.5)

When viewing a product with attributes in the front-end, beside each attribute checkbox (or radio button), a string such as

"ATTRIBUTES_PRICE_DELIMITER_PREFIX+€5.00ATTRIBUTES_PRICE_DELIMITER_SUFFIX
ATTRIBUTES_WEIGHT_DELIMITER_PREFIX+0.12KgATTRIBUTES_WEIGHT_DELIMITER_SUFFIX" is output.

The same thing I have noticed in online zen cart sites such as:
http://www.somsak2004.net/zentcart/ZenCart138_Fasion/index.php?main_page=product_info&cPath=48_45&products_id=90

or

http://www.comodus.nl/demo-shop/index.php?main_page=product_info&cPath=49_27&products_id=82&number_of_uploads=0&language=nl

It looks like some constant names from the internal code are literally output in the html conteng.
Is that a bug of zen cart, and how could that be fixed ?

https://www.zen-cart.com/tutorials/index.php?article=95

ok, thanks a lot. I found out in the file product_info.php greek lang pack version (the one from krom offered in the contributions) that the following lines were missing:

define('ATTRIBUTES_PRICE_DELIMITER_PREFIX', ' ( ');
define('ATTRIBUTES_PRICE_DELIMITER_SUFFIX', ' )');
define('ATTRIBUTES_WEIGHT_DELIMITER_PREFIX', ' (');
define('ATTRIBUTES_WEIGHT_DELIMITER_SUFFIX', ') ');

(I am impressed by the very good support this forum has....)