the response back from authorize.net is:
Line item 1 is invalid
this happens if the item information sent to the gateway does not meet the formatting specifications.
the item data being sent is:
x_line_item=<|>Direct Donation<|>I would like to donate directly to the school<|>1<|>20<|>YES&x_line_item=DD03<|>Run4Funds Donation<|>I am sponsoring a runner!<|>1<|>20<|>YES&x_line_item=DD04<|>Direct donation<|>I'm supporting a Student Runner!<|>1<|>21<|>YES
the first item in the cart does not have an ID. The item ID is not optional.