Ok, so I got a custom list with two columns: Project Name and Order No. I created a view of invoice totals in my SQL db (Columns: OrderNo; VAT; Total) and created the application definition file. I created a simple web part page on which I placed the Project list (as a normal List View Web part) and also added the BDC list web part. Both displaying 100%. Now I want to connect the two web parts so that I can choose a project on the left and it then filters the BDC list to only show the corresponding row where the Order No Equals the project selected on the left. So I edited the page, clicked on the project list view web part and chose Connections > Provide Row To > dbo.TableName. I then chose the connection option Get Filter Values From. The Provider Field Name is already the Order No from the project list and I then choose the order no from the BDC list as the Consumer Field Name and hit Next. It then asks for me for another field from the BDC list as the Consumer field name to correspond to the Project Name field from the Project List. (don't know why it wants another connecting field - Order No should be enough). Hitting Finish gets me the ol' Object Reference not set error: [NullReferenceException: Object reference not set to an instance of an object.] Microsoft.SharePoint.Portal.WebControls.BusinessDataListWebPart.GetBdcFilterData(IDictionary dataFromFilter) +119 Microsoft.SharePoint.WebPartPages.RowProviderConnectionAgent.RowReady(Object sender, RowReadyEventArgs rowReadyEventArgs) +382 Microsoft.SharePoint.WebPartPages.ListViewRowProviderInterface.FireMainIfAppropriate() +1403 Microsoft.SharePoint.WebPartPages.ListViewWebPart.PartCommunicationMain() +198 Microsoft.SharePoint.WebPartPages.Communication.WebPartConnector.PartCommunicationMain() +63 Microsoft.SharePoint.WebPartPages.Communication.PartCommunicationPhase.Invoke() +0 Microsoft.SharePoint.WebPartPages.Communication.ConnectionRuntime.FirePartCommunicationMain() +77 Microsoft.SharePoint.WebPartPages.SPWebPartManager.ActivateV2Connections() +750 Microsoft.SharePoint.WebPartPages.SPWebPartManager.ActivateV2ConnectionsAndSharePointDataFetch() +150 Microsoft.SharePoint.WebPartPages.SPWebPartManager.ActivateConnections() +136 System.Web.UI.WebControls.WebParts.WebPartManager.OnPageLoadComplete(Object sender, EventArgs e) +69 System.EventHandler.Invoke(Object sender, EventArgs e) +0 System.Web.UI.Page.OnLoadComplete(EventArgs e) +4470431 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3426 Am I doing this right? Can one actually connect a custom list view web part with a BDC List web part?