error 500 when inserting prices

[Golovior]

Hello,

First of all: We use this version: com_virtuemart.2.0.0_extract_first.zip

We've got a small problem with inserting prices in products.
We can create products without problem, as long as we don't fill in the prices of the products. When inserting a price, the shop itself (mainpage of the shop) gets a 500 Internal Error page.
This only gets fixed as soon as i'm deleting the record in the database (virtuemart_product_prices).

Is there a solution for this already?

Oww.. we're using the dutch languagepack too.

Thanks in advance!