Add to Cart in BO doesn't work - PS 1.5.3.1

[MarketingPro]

We are unable to make orders through the backoffice. We can select the user and the product, but when we click the "Add to cart" button it only works when "euro" is selected as currency (if other currency is selected, nothing happens after clicking "Add to cart").

 

Even with "euro" selected, you can't add more than one product or delete the already added product, so I guess something is very wrong with the add to cart functionality.

 

After selecting "euro" as currency and adding 1 product, when we try to finish the order we get 9 errors of required fields (we are using spanish, but I can translate to you it if its relevant):

 

9 errores 
El campo id_cesta es necesario.
El campo id_cliente es necesario.
El campo id_transportista es necesario.
El campo Pago: es necesario.
El campo total_pagar es necesario.
El campo total_pago_real es necesario.
El campo total_productos es necesario.
El campo total_productos_wt es necesario.
El campo tipo_conversión es necesario.

Searching for this errors I've reached http://forge.prestashop.com/browse/PSCFV-4761 and http://www.prestashop.com/forums/topic/192618-add-to-cart-in-bo-doesnt-work-ps-151/?p=955533. I've tried that code but it doesn't change anything, still not working as expected. Flushed caches but still the same.

 

In http://www.prestashop.com/forums/topic/192618-add-to-cart-in-bo-doesnt-work-ps-151/?p=1021361 Benjamin Utterback says that problem has been fixed in 1.5.2 and we are using 1.5.3, so I guess ours is a different problem...

 

We've able to complete orders from back-office perfectly last week, but now is not working. We haven't made any code changes lately (only CSS) and no new modules, so we don't have any clue of what could be causing the problem.

 

Any ideas or possible solutions?

 

 

[MarketingPro]

Nobody have any clue?