Can not do shipment for order

Hi, just started to test nopCommerce (great app BTW)
I did setup paypay standard , finished order and now when i go to control panel, click that order and try to mark it as shipped i get error:
Can not do shipment for order.
NopSolutions.NopCommerce.Common.NopException: Can not do shipment for order. at NopSolutions.NopCommerce.Common.Orders.OrderManager.Ship(Int32 OrderID, Boolean notifyCustomer) in D:\Work\Own\NopCommerce\Solution\NopCommerce\Nop.Common\Orders\OrderManager.cs:line 1012 at NopSolutions.NopCommerce.Web.Administration.Administration_OrderDetails.btnSetAsShipped_Click(Object sender, EventArgs e) in c:\Documents and Settings\USER_HERE\My Documents\Visual Studio 2008\WebSites\NopCommerceWeb\Administration\OrderDetails.aspx.cs:line 185

Then when i cleared cache, and go to that order again it is mark as complited ans shipped

I did few more orders and was unable to repeat that error.

Have you ordered pre-defined products (test data)? If 'Yes', what are theirs IDs?

Yes, ID # 39 it is epson cx9400
on order details page it shows product name and link to ProductVariantID=45
as i said before i could not repeat this error