Assembly reference

[Craftor]

Hi all

The search is down so apologies if this has been answered before.

I am currently working with Microsoft Content Management Server 2002 - and it gives me the following error when I try to declare a variable:
The type 'Microsoft.ContentManagement.Interop.Publishing.IRcwPlaceholders' is defined in an assembly that is not referenced. You must add a reference to assembly 'Microsoft.ContentManagement.Interop.Publishing'.


The line of code I am using to declare the variable is:

PlaceholderCollection pPlaceholders = new PlaceholderCollection();

I have the CMS reference set at the top:

using Microsoft.ContentManagement.Publishing;
using Microsoft.ContentManagement;

When I try to add the reference (right click on the References folder in the Solution Explorer) - I can browse to the required reference (in WINNT/assembly) but it won't let me add it ... I can click on it but it just won't open the file.

Does anyone know of a way around this?

Thanks as always

Craftor