尝试:

Server.MapPath("~/Path");  //using '~' should work. 

在ASP.Net 1.x中，Server.MapPath("..")在较早的版本中可以正常工作.
较新的版本不支持".."，建议改用〜".

In ASP.Net 1.x, Server.MapPath("..") works fine in the older versions.
The newer version does not support ".." and it is recommended to use "~" instead.