原因：IIS没有注册
解决办法：
方法一：
在CMD中进入目录C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727，运行aspnet_regiis
1、aspnet_regiis -ga administrator（administrator为当前用户）
2、aspnet_regiis -i （注册IIS）
3、iisreset /noforce （重启IIS）
操作详细：
C:\Documents and Settings\Administrator>cd c:\\windows\\microsoft.net\\framework\\v2.0.50727
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727>aspnet_regiis -ga administrator
Start granting administrator access to the IIS metabase and other directories us
ed by ASP.NET.
Finished granting administrator access to the IIS metabase and other directories
used by ASP.NET.
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727>aspnet_regiis -lv
2.0.50727.0 Valid C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\as
pnet_isapi.dll
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727>aspnet_regiis -i
Start installing ASP.NET (2.0.50727).
..............
Finished installing ASP.NET (2.0.50727).
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727>aspnet_regiis -lv
2.0.50727.0 Valid (Root) C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\as
pnet_isapi.dll
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727>iisreset /noforce
Attempting stop...
Internet services successfully stopped
Attempting start...
Internet services successfully restarted
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727>
方案二：
可以建立一个的bat文件.以下为代码:
@echo off
pause
aspnet_regiis -ga administrator
aspnet_regiis -lv
aspnet_regiis -i
aspnet_regiis -lv
iisreset /noforce
@echo off
pause
将以上文本保存成bat文件.
复制到C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727 后运行
问题详情：
[HostingEnvironmentException: Failed to access IIS metabase.]
System.Web.Configuration.MetabaseServerConfig.MapPathCaching(String siteID, VirtualPath path) +637
System.Web.Configuration.MetabaseServerConfig.System.Web.Configuration.IConfigMapPath2.MapPath(String siteID, VirtualPath vpath) +9
System.Web.Hosting.HostingEnvironment.MapPathActual(VirtualPath virtualPath, Boolean permitNull) +174
System.Web.Hosting.HostingEnvironment.MapPathInternal(VirtualPath virtualPath, Boolean permitNull) +51
System.Web.CachedPathData.GetConfigPathData(String configPath) +341
System.Web.CachedPathData.GetConfigPathData(String configPath) +234
System.Web.CachedPathData.GetApplicationPathData() +38
System.Web.CachedPathData.GetVirtualPathData(VirtualPath virtualPath, Boolean permitPathsOutsideApp) +8802175
System.Web.Configuration.RuntimeConfig.GetLKGRuntimeConfig(VirtualPath path) +117
