我下的VisualC++6为什么编译错误呢？

如果你是按照初始路径安装vc6.0的，路径应为：
executatble files:
C:\Program Files\Microsoft Visual Studio\Common\MSDev98\Bin
C:\Program Files\Microsoft Visual Studio\VC98\BIN
C:\Program Files\Microsoft Visual Studio\Common\TOOLS
C:\Program Files\Microsoft Visual Studio\Common\TOOLS\WINNT

include files:
C:\Program Files\Microsoft Visual Studio\VC98\INCLUDE
C:\Program Files\Microsoft Visual Studio\VC98\MFC\INCLUDE
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE

library files:
C:\Program Files\Microsoft Visual Studio\VC98\LIB
C:\Program Files\Microsoft Visual Studio\VC98\MFC\LIB

source files:
C:\Program Files\Microsoft Visual Studio\VC98\MFC\SRC
C:\Program Files\Microsoft Visual Studio\VC98\MFC\INCLUDE
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE
C:\Program Files\Microsoft Visual Studio\VC98\CRT\SRC

如果你装在其他盘里，则仿照其路径变通就行(我就是装在D盘)。
关键是microsoft visual studio\ 后面的东西要相同。