Gladly PHP says exactly what is wrong. You just have to read the error message:
Now what does this mean?
Your component is using a php class library which is called "cafepressbox". When you start the component, it tries to register this class in PHP. During this process PHP suddenly realises, that there already exists a class with the same name. As a class can only be registered to PHP once, PHP suddenly interrupts and drops the error message.
How can you solve this?
In most cases the error wasn't made by the user, but by the developer. And this error is a common one. After the develper coded the component, he maybe thought that a module would be a nice addition to his component. In this module he uses many functions, he already has coded in his component. So why invent the wheel twice? He just loads the class library and think he is safe. But he is not!
When you have already declared your class in the module, the component will fail to initialize the class again (if the component is loaded after the module, otherwise it's vice versa). So the developer must check, if the class is already declared if so, he didn't need to do this again.
You should try to turn off the module and see, if the component now loads fine. If it will, please inform the corresponding author (see XML file) and point him to this thread. If this is not the solution, than damn, it took me 5 minutes to explain this so very detailed...
