Hi I'm getting some error after switching version of infragistics

Error    159    The type 'Infragistics.Excel.ExcelDefaultableBoolean' exists in both '.......bin\Infragistics2.WebUI.Excel.v10.2.dll' and '....\bin\Infragistics2.Web.v10.2.dll'    some.aspx.cs    2209    98

or

Error    102    The type 'Infragistics.Excel.HorizontalCellAlignment' exists in both '........\bin\Infragistics2.WebUI.Excel.v10.2.dll' and '...........\bin\Infragistics2.Web.v10.2.dll'    some.aspx.cs    412    107

I have checked with reflector and those namespaces exists in those two assemblies.

Hwat should I do to make it working