I'm converting a large project to VS2008 from VS6 and i'm getting a strange template problem on VS2008 only, hope someone can help.

I have an include file which has the line:-
class CMap;

but when I compile in VS2008 i get error:-
error C2990: 'CMap' : non-class template has already been declared as a class template

It is been used in other includes no problem.

if I take that line out 'class CMap;' then I get error:-
error C2955: 'CMap' : use of class template requires template argument list

Any ideas on how to fix this?