Add-WindowsFeature cmdlet to install the necessary operating system components

We ran in ps as admin the below command IAW following technet article on our 2008r2 server  http://technet.microsoft.com/en-us/library/bb691354.aspx 

  "Add-WindowsFeature NET-Framework,RSAT-ADDS,Web-Server,Web-Basic-Auth,Web-Windows-Auth,Web-Metabase,Web-Net-Ext,Web-Lgcy-Mgmt-Console,WAS-Process-Model,RSAT-Web-Server,Web-ISAPI-Ext,Web-Digest-Auth,Web-Dyn-Compression,NET-HTTP-Activation,RPC-Over-HTTP-Proxy -Restart"

Received following error

The term 'Add-WindowsFeature' is not recognized as the name of a cmdlet, function, script file, or operable program. Ch
eck the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:19
+ Add-WindowsFeature <<<<  NET-Framework,RSAT-ADDS,Web-Server,Web-Basic-Auth,Web-Windows-Auth,Web-Metabase,Web-Net-Ext,
Web-Lgcy-Mgmt-Console,WAS-Process-Model,RSAT-Web-Server,Web-ISAPI-Ext,Web-Digest-Auth,Web-Dyn-Compression,NET-HTTP-Acti
vation,RPC-Over-HTTP-Proxy -Restart
    + CategoryInfo          : ObjectNotFound: (Add-WindowsFeature:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException
We have performed all procedures up to this point in above prerequisites list of above.

Anything we are missing which is possible as this is a tricky process exch 2003 -> exch2010

Thanks

Craig