C2653: is not a class or namespace name

--------------------Configuration: ik - Win32 Debug--------------------
Compiling...
engine.cpp
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\engine\engine.inl(6) :
error C2653: 'playlist' : is not a class or namespace name
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\engine\engine.inl(6) :
error C2065: 'play' : undeclared identifier
system.cpp
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\engine\engine.inl(6) :
error C2653: 'playlist' : is not a class or namespace name
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\engine\engine.inl(6) :
error C2065: 'play' : undeclared identifier
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\system\system.cpp(87) :
error C2653: 'playlist' : is not a class or namespace name
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\system\system.cpp(87) :
error C2065: 'callback' : undeclared identifier
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\system\system.cpp(112) :
error C2653: 'playlist' : is not a class or namespace name
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\system\system.cpp(112) :
error C2065: 'load' : undeclared identifier
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\system\system.cpp(139) :
error C2653: 'playlist' : is not a class or namespace name
c:\ikfullsdk-2004-03-12 (ik)\ikfullsdk-2004-03-12\system\system.cpp(139) :
error C2065: 'terminate' : undeclared identifier
Error executing cl.exe.

ik.exe - 10 error(s), 0 warning(s)

Don't know why the above messages come up... I have the playlist class like
the following and also with all include path set
//////////////////////////////////////////////// playlist.h

#ifndef IKPLAYLIST_H
#define IKPLAYLIST_H

#include "file.h"
#include "music.h"

namespace ik
{
class playlist
{
public:
 enum
 {
  MAX_TRACKS =16
 };

 static bool load(const char* filename);
 static void terminate();

 static void play();
.....
};

#include "playlist.inl"
}

#endif

////////////////////////////////////////////////// engine.inl
inline void engine::set_cinematic()
{
 if (cinematic.get_event())
 {
  cinematic.destroy();
  playlist::play();
  options&=~CINEMATIC;
 }
}

This is an open source project and to be built with VC++ 6.0....
Thanks
Jack