通过下面的链接找到了解决方案http://www.cnblogs.com/li7125502/archive/2007/09/13/891678.html
错误信息：
Runtime Error
Description: An application error occurred on the server. The current custom error settings for this application prevent the details of the application error from being viewed.
Details: To enable the details of this specific error message to be viewable on the local server machine, please create a
将customErrors mode改为Off后得到错误信息如下：
Parser Error
Description: An error occurred du ring the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Data at the root level is invalid. Line 1, position 1.
Source Error:
Line 1:
Line 2:
Line 3:
Description: An error occurred du ring the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Data at the root level is invalid. Line 1, position 1.
Source Error:
Line 1:
Line 2:
Line 3:
解决方案总的来说，很简单，就是删除c:\Inetpub\wwwroot\wss\VirtualDirectories\80(or your port #)\App_Browsers\ compat.browser
然后就可以重新访问了。