r - SQL Server 2016 R 服务。连接错误

Question

我之前安装了 SQL Server 2016，想试试它的 R Services。我浏览了本教程并来到第 2.5 步，我必须通过此脚本测试连接：

exec sp_execute_external_script  @language =N'R',  
@script=N'OutputDataSet<-InputDataSet',    
@input_data_1 =N'select 1 as hello'  
with result sets (([hello] int not null));  
go  

错误是：

Msg 39021, Level 16, State 1, Line 1
Unable to launch runtime for 'R' script. Please check the configuration of the 'R' runtime.
Msg 39019, Level 16, State 1, Line 1
An external script error occurred: 
Unable to launch the runtime. ErrorCode 0x80070490: 1168(Element not found.).

我用谷歌搜索，本教程指出我必须卸载然后安装RegisterRExt.exe. 我这样做了。重新启动计算机和实例服务。但错误不断出现。

我该如何解决？