帮忙看看这是怎么回事啊

下面是用VC6.0编译vxd文件时出现的错误信息，请问如何设置COMPILER ？

--------------------Configuration: MY - Win32 Release--------------------
Microsoft (R) Program Maintenance Utility   Version 6.00.8168.0
Copyright (C) Microsoft Corp 1988-1998. All rights reserved.
C:\\PROGRA~1\\NUMEGA\\VTOOLSD\\include\\vtoolsd.mak(217) : fatal error U1050: COMPILER must be defined to MS5, MS6 or BCB3
Stop.
Error executing NMAKE.

MY.vxd - 1 error(s), 0 warning(s)