Have you added the correct references to your project? They are undoubtedly different for different versions of MM.

>Hello all,
>
>I am finally attempting to convert my web app from VS 2008 and MM.NET 3.6 to VS 2010 and MM.NET 4.0. I am now attempting to compile my Telerik Web Controls for MM.NET to the new version and when I build the project I get the following error:
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>Error 1 The command "Copy "C:\Program Files (x86)\Mere Mortals .NET Framework 2010\Third Party Components\Telerik Web Controls\bin\Debug\OakLeaf.MM2010.WebForms.Telerik.*" "C:\Program Files (x86)\Mere Mortals .NET Framework 2010\Third Party Components\Telerik Web Controls\"
>"C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools\GACUTIL" /i "C:\Program Files (x86)\Mere Mortals .NET Framework 2010\Third Party Components\Telerik Web Controls\OakLeaf.MM2010.WebForms.Telerik.dll" /f" exited with code 3.
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>Any ideas on this error?
>
>TIA