Error on inserting records in Sales Orders!

Error on inserting records in Sales Orders!

Hello,

I am trying to insert a Sale Order with following xml code, but I receive this error: 4832Problem occurred while processing the request.

xml code:

<SalesOrders>

<row no="1">

<FL val="Subject">xxx</FL>

<FL val="Account Name"> xxx </FL>

<FL val="Contact Name"> xxx </FL>

<FL val="Billing First Name"> xxx </FL>

<FL val="Billing Last Name"> xxx </FL>

<FL val="Billing City"> xxx </FL>

<FL val="Billing ZIP"> xxx </FL>

<FL val="Billing Country"> xxx </FL>

<FL val="Billing Street"> xxx </FL>

<FL val="Billing Fiscal Code"> xxx </FL>

<FL val="Product Details">

<product no="1">

<FL val="Product ID">37</FL>

<FL val="Product Name">eCommerce Update!</FL>

<FL val="List Price">40.16</FL>

<FL val="Quantity">1</FL>

<FL val="Amount">40.16</FL>

<FL val="Discount">0</FL>

<FL val="Tax">0.00</FL>

<FL val="Total">40.16</FL>

<FL val="Sub Total">40.16</FL>

<FL val="Grand Total">40.16</FL>

</product>

</FL>

<FL val="Grand Total">45000</FL>

</row>

</SalesOrders>'

The product id is ok, because I imported the products myself...

When I delete the xml code about product, it works. What am I doing wrong? Please help!