It is returning a 270 error - line item 1 is invalid. I have sent you the WAAuthNet_postedValues array as well as WAAuthNet array in a PM. The credit card number, login and transaction key have been removed for security.
It looks likes the issue may be here: x_line_item=437<|><|><|>1<|>3.5<|>YES
The Name of the product and the description are not being sent.
I thought it may be because of the ampersand or long product name for this particular product but it is the same result no matter what the product. Here's the posted line item of a different product: x_description=1 Teen Issues Thumball (3112)&x_line_item=3112<|><|><|>1<|>14.949999809265<|>YES