Hi,
Then it probably means that you restricted your payment methods to your shipping methods and have the "force shipping regardless of weight" setting turned off.
Thus, if your product doesn't have any weight, no shipping method is needed and thus no payment method shows up.
But since a payment method is necessary to finish the checkout, the system doesn't let you finish.
Also, normally, at that point you should get an error message.
If you don't, it's probably that your Joomla template is not displaying messages:
www.hikashop.com/support/support/documen...tibility-issues.html
That's just a theory since I don't know how you configured your payment methods, shipping methods, checkout and products... but it's the only one I can think of at the moment.