Unknown server tag 'telerik:ReportViewer'.

[Marc Fearby]

I'm getting the following error in all Telerik reports in a .NET 4.0 web app I have recently taken over from somebody else who has resigned. Thus far I've had success by installing required MSI files and removed hard-coded versions in web.config files and adding references to the DLL files. But this approach hasn't worked for Telerik ReportViewer. Am I missing something? I've installed Reporting Q3 2010 and added references to Telerik.Reporting.dll and Telerik.ReportViewer.WebForms.dll and also ticked quite a few related namespaces below these references in the properties for the solution, but am getting nowhere. I have never used Telerik before but like what I see so far, apart from these errors :-(

Here's the error (and thanks):

 

Server Error in '/' Application.

---

Parser Error

Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.

Parser Error Message: Unknown server tag 'telerik:ReportViewer'.

Source Error:

Line 3: </asp:Content> Line 4: <asp:Content ID="Content2" ContentPlaceHolderID="cphReport" runat="server"> Line 5: <telerik:ReportViewer ID="ReportViewer1" runat="server" Report="ReportsLib.SummaryByActivity, ReportsLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" Line 6: Skin="Office2007" Width="100%" Height="700px" DocumentMapVisible="False" Line 7: ShowZoomSelect="True">

Source File: /MyReport.aspx    Line: 5

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Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.225

[Marc Fearby]

Now I don't know what to make of the problem. This morning I went and ticked anything that looked like a Telerik reference and added it to see if it would make a difference. It didn't. So I decide to see if I can drag the control onto the page and re-configure it the same as the "broken" one, and lo and behold, it works. Here are the two tags (the first one is the broken one and the second one works):

<telerik:ReportViewer ID="ReportViewer1" runat="server" Report="ReportsLib.SummaryByActivity, ReportsLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
        Skin="Office2007" Width="100%" Height="700px" DocumentMapVisible="False"
        ShowZoomSelect="True">
</telerik:ReportViewer>

<telerik:ReportViewer ID="ReportViewer2" runat="server" Report="ReportsLib.SummaryByActivity, ReportsLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
        DocumentMapVisible="False" Height="700px" ShowZoomSelect="True" Width="100%">
</telerik:ReportViewer>

However, after noticing that the only difference is the skin setting, I comment-out the second one and run with the first one, and now it works. What was I doing wrong before? I'm stumped.

Thanks.