If your module does not work as expected, here are a few ways to find help.
PrestaShop has built a special online tool to help you discover possible issues within your code.
You can access it here: https://validator.prestashop.com/auth
Make sure to validate your module before you submit it to the Addons marketplace! Indeed, the Addons team will refuse to accept a module that is not at least valid.
Join our forums at http://www.prestashop.com/forums/, and search for an answer using the relevant keywords. If your search needs refining, use the advanced search form. And if your search doesn't yield anything useful, create a new thread, where you can be as wordy as necessary when writing your question; you will need to register first.
Some forums keep certain threads pinned on top of all threads; they contain some useful information, so be sure to read them through.
If it turns out your issue stems from a PrestaShop bug rather than your code, please do submit the issue in the PrestaShop bug-tracker: http://forge.prestashop.com/ (you will need to register). This enables you to discuss the issue directly with the PrestaShop developers.
Official website for the PrestaShop tool, its community, and the company behind it.
Marketplace for themes and modules.
Host your shop with us!