Issue is resolved, Need to change little bit code in product.php (catalog >> controller >> product >> product.php). Actually that issue because of opencart 1.5.3.1 product table update on opencart version 1.5.4.1. 
Thank You.
My last opencart theme http://themeforest.net/item/anycart-elegant-and-responsive-opencart-theme/3005425?sso?WT.ac=category_item&WT.seg_1=category_item&WT.z_author=stevemun7 Anycart is running fine on demo link. But three buyers comment that after install this theme it shows issue on there live url.
Issue mention below.
Notice: Error: Table ‘opencart.product_tag’ doesn’t exist Error No: 1146 SELECT * FROM product_tag WHERE product_id = ‘50’ AND language_id = ‘1’ in /public_html/newsite/system/database/mysql.php on line 49
Theme supported opencart version 1.5.4.1 the latest one also running on my demo.
For last three negative comments my theme is not selling good. Please suggest me or give some solution if some one knows. I will be great full always.
