We received reports the free coupon didn't work and showed database errors when we subscribed to a location in the 2.8.0 release, another issue was a fatal error.
Please follow the below instruction to fix these problems:
In modules/mod_cmgroupbuying_more_coupons/helper.php, change line 86 from
$locationString = ModCMGroupBuyingMoreDealsHelper::getCouponsInLocation($locationId);
to
$locationString = ModCMGroupBuyingMoreCouponsHelper::getCouponsInLocation($locationId);
In components/com_cmgroupbuying/models/freecoupon.php, change line 230 from
$query->where($db->quoteName('id') . ' IN (' . $dealIdString . ')');
to
$query->where($db->quoteName('id') . ' IN (' . $couponIdString . ')');
We updated cmgroupbuying_2.8.0_unzip_first.zip package in our download area, if you download this package after Thursday, 27 February 2014, 01:45:00 UTC (Thursday, 27 February 2014, 08:45:00 ICT UTC+7 hours - our timezone), you will not have this bug.
Our apology for any inconvenient caused and thank you very much for using CMGroupBuying and contributing to make it better!
Please feel free to contact us if you have any question.