Error again

i get this error

Enable-ProjectServerLicense : The term 'Enable-ProjectServerLicense' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or
if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ Enable-ProjectServerLicense -Key 
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (Enable-ProjectServerLicense:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

ANY IDEA?