the response coming back from Authorize.net is "Line Item 1 is Invalid", this error happens if the cart description or other information passed for the product is either to long or contains invalid characters.
the information being passed for the item is:
x_line_item=979<|>Zija Energy Free Trial Pack<|>Zija Energy Trial Pack <|>
I think the problem is the two non breaking space html entities at the end of the cart description:
Zija Energy Trial Pack
try removing those.