使用下面的LoadLibraryEx可以成功
HMODULE hmod = LoadLibraryEx("C:\\MyDll.dll", NULL, DONT_RESOLVE_DLL_REFERENCES )
看了下MSDN:
DONT_RESOLVE_DLL_REFERENCES  If this value is used, and the executable module is a DLL, the system does not call DllMain for process and thread initialization and termination. Also, the system does not load additional executable modules that are referenced by the specified module.
If this value is not used, and the executable module is a DLL, the system calls DllMain for process and thread initialization and termination. The system loads additional executable modules that are referenced by the specified module.
也就是说不会执行dll入口函数,LoadLibrary会在哪个环节出错呢?
边思考边等高手...

找到原因:
见http://blog.csdn.net/ymt/article/details/4706935
感谢该博主
在此演了把自问自答,呵呵,结贴 结贴

顺便补充下我的解决方法,不是帖子里面的方法,更简单,但前提是所有自己的dll要在一个目录下:
LoadLibraryEx("C:\\MyDll.dll", NULL, LOAD_WITH_ALTERED_SEARCH_PATH);