Blank page after new product save

[Elnino]

Hi,

Running J1.7.3, did a fresh install of the version VM2 2.0.0RC3 f.
When I created a new product in the admin, the product is created but I've got a blank page on save. None of the product info is saved but Produt SKU, product Name and Product alias. All the other fields are not saved ...

If I go back later to the product details in the admin section without changing any fields and I click "save" same trouble: blank page. I can't change anything on this product. Same thing if I create a new product.

I've added error_reporting(E_ALL); in the index.php of the administrator folder but I don't get any messages either, just a blank page (maybe it's not the right way of doing this). I don't know what to do!

Any idea?

Thanks