The error that is being returned is Line item 1 is invalid. This means that there is a problem with the first item in the cart that you passed to the gateway in your test. The rules for the line item are found here in the Authorize.NET AIM guide:
AIM_guide.pdf
On page 20 it lists the requirements for a line item. Here are some of the restrictions:
Item ID<|>
Up to 31 characters
<|>item name<|>
Up to 31 characters
<|>item description<|>
Up to 255 characters
Looking at the values you got back it seems that there might be a problem with the description you are using. It looks like there might be some returns in your description. You should try removing these to see if it will accept this item. Do you get this error with any other items? You should test it out with one item at a time to see if you have any other products that do not have this error.
