If you purchased one of our products from the Extension Warehouse, you do not need a license key.
Rather, you need to login to the Extension Warehouse from inside SketchUp using the same email account that you used when you purchased. Then, go to 'My Extensions' and install your purchased plugin.
If you did NOT purchase from the Extension Warehouse, click here to have your license key resent. Make sure you select the correct product when filling out the form.