New Post: I installed NB Store but I have a problem

good morning to all.
I installed NB Store but I have a problem.

Error: NB_Store_ProductList is not currently available. DotNetNuke.Services.Exceptions.ModuleLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. in NEvoWeb.Modules.NB_Store.ProductTemplate.AddToRelated_DataBinding (Object sender, EventArgs e) in System.Web.UI.Control.OnDataBinding (EventArgs e) in System.Web.UI.Control.DataBind (Boolean raiseOnDataBinding) in System.Web. UI.Control.DataBind () in System.Web.UI.Control.DataBindChildren () in System.Web.UI.Control.DataBind (Boolean raiseOnDataBinding) in System.Web.UI.Control.DataBind () at System.Web. UI.WebControls.DataList.CreateItem (Int32 itemIndex, ListItemType itemType, Boolean DataBind, Object dataItem) in System.Web.UI.WebControls.DataList.CreateControlHierarchy (Boolean useDataSource) in System.Web.UI.WebControls.BaseDataList.OnDataBinding (EventArgs e) in System.Web.UI.WebControls.BaseDataList.DataBind () in NEvoWeb.Modules.NB_Store.ProductList.populateList (Int32 CatID) in NEvoWeb.Modules.NB_Store.ProductList.Page_Init (Object sender, EventArgs e) --- end of inner exception stack trace ---

Can anyone help me?
thanks
Corrado