G'day,

I fixed the problem for my setup by changing from:

Code:
$sweight = $shipping_weight*1000;
to...
Code:
 
$sweight = $shipping_weight*1000;
if ($sweight < 1) {
 $sweight = 300;
}
in my various Australia Post module files.

In other words, if the order has no weight, set it to 300 grams.

Best Regards, Lloyd Borrett.