madsqrl,

I tried out the module with alpha 8 and I did get the same error you were getting. Here are the technicalities for anybody interested. There was a change to the argument passed to hook_order when $op is 'update'. $arg1 used to be an order id, now it is the whole order object. If you put the following code at the beginning of the 'update' case, it should fix things:

if (!is_string($arg1)) {
$arg1 = $arg1->order_id;
}

I will update the .module file soon, so if you find it easier, just get the new file. Please let me know if this fixes your problem.

Cheers!

EDIT: the file has been updated