Aha ... AUD is naturally supported by PayPal.
The PayPal IPN module converts non-supported currencies to USD, which, since you don't have USD defined as a currency, ultimately ends up being 0.
The module supports CAD, EUR, GBP, JPY, USD, AUD.
If you wish to attempt to override that, you can try the following edit:
/includes/modules/payment/paypal.php
approx line 169:
Code:
if (!in_array($my_currency, array('CAD', 'EUR', 'GBP', 'JPY', 'USD', 'AUD'))) {
you could replace that line with this:
Code:
if (!in_array($my_currency, array('CAD', 'EUR', 'GBP', 'JPY', 'USD', 'AUD', 'CHF', 'CZK', 'DKK', 'HKD', 'HUF', 'NOK', 'NZD', 'PLN', 'SEK', 'SGD', 'THB'))) {
You'll want to do the same in /includes/modules/payment/paypal/paypal_functions.php around line 74
BTW - nice site.