I have had the same issue, and I’ve sent a message to Instinct concerning the problem. I believe the issue is simply an omission of php files in the linkpointpem directory – if you look (perhaps through FTP) in this directory in the gold_cart_files you will find it empty. Since the require() function is called and nothing is in /home/meupda/public_html/loja/wp-content/plugins/wp-shopping-cart/gold_cart_files/merchants/linkpointpem, the plugin has a fatal error.
I really hope Instinct answers my request for this missing data soon, or perhaps comes up with an explanation. In the meantime, I’m investigating removing this merchant from my php files, as I don’t use this gateway anyway.