Hi,
ohh no, it can't be related to order ID. But FYI, use the "confirmed" order ID. Pending orders are periodically deleted from the system.
If the slider doesn't work, then it must be because of something else. Do you also have a website in a live server? (where i can browse and check your website?) if so, install/publish the module to the live server and provide me the URL where the module doesn't show any product in it. I want to check the source codes, and try to figure out what goes wrong.
regards.