dj5000: I change the web.config part as in clasic mode. now the error is no longer on the web.config but on the containing page itself: Parser Error Message: Could not load file or assembly 'DotNetGallery' or one of its dependencies. The module was expected to contain an assembly manifest. Line 2: MasterPageFile="~/tabledMasterPage.master" %>Line 3: Line 4: <%@ Register Assembly="DotNetGallery" Namespace="DotNetGallery" TagPrefix="DotNetGallery" %>Line 5: Line 6: <asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server"> Source File: /AlbumView.aspx Line: 4 any ideas? Hi dj5000, Please add reference to file DotnetGallery.dll and try again. Regards, Ken