Some people have trouble with their ecommerce software after installation to their online store. For those who do run into problems after the installation they probably did not do it right. If you are not familiar with installing scripts you should speak to a programmer and hire them to install your script. If you already have a shopping cart software and you are running into problems after the installation has already been done properly (since it did work when you first used). The problem might be in the program itself. These problems are harder to detect and fix, a professional has to go through your software to see what the problem is. This might cost a bit, if there is a support team that comes with your shopping cart program, talk to them first because they know more about the program than programmers since they have probably had to answer similar questions from others.