Don't allow to validate order if product price is 0

[dooban]

I am on PS 1.6.1

I do regular automatic imports on 40000 products, when I have product combinations and any of this products are in a cart, the total price changes to 0. The problem is that the id of product combination changes after every import.

But my problem is:

When there is a product in the cart with price = 0 and the order is confirmed, an error is produced and the cart is lost and the order not proceseed. Before I repair this error I need:

I need a validation that doesn't allow to confirm an order, showing a message to the user that says smth like 'You have products in the cart with price = 0, please fix it".

Please help.

 

Thanks

[dooban]

Anyone ?, I just need to know how to show a message to the user before order validation if a criteria is met for a product that is in the cart.

 

[dooban]

Please please

I need a validation that doesn't allow to confirm an order if there is a product in the cart with price = 0. It should show a message to the user that says smth like 'You have products in the cart with price = 0, please fix it".

Thanks