Getting Assemly related error

i Add one third party dll in my project when i run the project i get this type of error i don't know what to do plz sent some suggestion

      "An assembly with the same simple name 'Interop.WMPLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null has already been imported. Try removing one of the references or sign them to enable side-by-side".