When trying to compile a .dll, I'm getting an error with the interface keyword

When trying to compile a .dll, I'm getting an error with the interface
keyword

I have set up a project in Visual Studio to create a .dll. I have included
an external library in the project which uses the keyword "interface".
This is giving me the following error:
error C2146: syntax error : missing ';' before identifier 'INuiAudioBeam'
These are the lines of code where the error occurs:
#ifndef __INuiAudioBeam_FWD_DEFINED__
#define __INuiAudioBeam_FWD_DEFINED__
typedef interface INuiAudioBeam INuiAudioBeam; //Error on this line