First of all I want to say that this is an ugly way of doing things. Most probably the ugliest. If you didn't want to add the company name in here I will. It's interiorwebdesign.com. Most probably the things sent to their server are the magento version, the extension version and the url of your website. You can check for sure by doing base64_decode on the value of the sdata parameter sent to them. I don't know what the answer should be if your licence is correct, but in case there is an error this is the response:
checkout.o_p_c_l_s = '2';
deljsphp();
Look in the code for a function called deljsphp. I think that disables your checkout.