excel and word primary interop reference trouble in a class

in a class library there exists references and use of Microsoft.Office.Interop.Excel and office core from PIA

now I tried to add new class using reference to Microsoft.Office.Interop.Word. I add reference he project from PIA for word.

and then tried adding

using  Microsoft.Office.Interop.Word;

  However the "Word" above" got flagged

Error 236 The type or namespace name 'Word' does not exist in the namespace 'Microsoft.Office.Interop' (are you missing an assembly reference?) 

after commenting out the using,

I then tried using fully qualified

private Microsoft.Office.Interop.Word.Document document;

the Word after Interop.Word is again flagged

Error 247 The name 'Word' does not exist in the current context IeWindowsFormsControlLibrary

what can I do other than take this new class out to a separate class lib project?