running psake from Powershell window

[gregor suttie]

Im importing psake using import-module psake

I can see that the module has been loaded fine, when I try to do the following:-

Invoke-psake .\Build.ps1 I get :--

CleanupEnvironment : The term 'CleanupEnvironment' 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 C:\Downloads\psake-master\psake-master\psake.psm1:453 char:9
+         CleanupEnvironment
+         ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (CleanupEnvironment:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

GetCurrentConfigurationOrDefault : The term 'GetCurrentConfigurationOrDefault' 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 C:\Downloads\psake-master\psake-master\psake.psm1:424 char:26
+         $currentConfig = GetCurrentConfigurationOrDefault
+                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (GetCurrentConfigurationOrDefault:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

What on earth am I doing wrong - being stupid I guess but I cant see what's wrong