2 shipping problems (I'm a newbie)

[katriniac]

I just launched my shop yesterday and found a problem.

Out of the 300 products we offer, a few do not behave in the shopping cart when a customer tries to check out.

 

I have encountered 3 distinct problems which do not overlap with each other:

1. Shipping will increase $6.65 per item, regardless of the weight or dimension of product.

2. No carriers will be available

3. A free shipping promo code results in no carriers being available (this even happens with products which behave themselves).

 

Other information to help you help me:

- Using PS version 1.6.1.4

- We use just one shipment module, the All-in-one USPS made by Prestashop.

- This module works perfectly when I have any of the 200+ non-problem products in the cart.

- When I compare the problem products with the non-problem products, there is no difference in the settings.

 

Is this a problem anyone else has had? How do I fix it? Do I need to buy one of Presta-Shop's support plans? I don't do any coding myself, so I can't fix it by looking at the code.

Thanks for helping this newbie!