Dúvida no Ex. 1 da Aula 1 - Começando com entity framework

Ao tentar instalar o entity framework, seguindo as instruções, deu alguns erros ao usar o comando:

install-package entityframework.commands -pre

E me devolveu o seguinte:

Where-Object : Cannot bind parameter 'FilterScript'. Cannot convert the "Name" value of type "System.String" to type "System.Management.Automation.ScriptBlock".
At C:\Workspace\Projetos .NET\EntityFramework\LojaEntity\packages\EntityFramework.Commands.7.0.0-rc1-final\tools\init.ps1:3 char:19
+ if (Get-Module | ? <<<<  Name -eq EntityFramework) {
    + CategoryInfo          : InvalidArgument: (:) [Where-Object], ParameterBindingException
    + FullyQualifiedErrorId : CannotConvertArgumentNoMessage,Microsoft.PowerShell.Commands.WhereObjectCommand

Join-Path : Cannot bind argument to parameter 'Path' because it is null.
At C:\Workspace\Projetos .NET\EntityFramework\LojaEntity\packages\EntityFramework.Commands.7.0.0-rc1-final\tools\init.ps1:7 char:25
+ Import-Module (Join-Path <<<<  $PSScriptRoot EntityFramework.psd1) -DisableNameChecking
    + CategoryInfo          : InvalidData: (:) [Join-Path], ParameterBindingValidationException
    + FullyQualifiedErrorId : ParameterArgumentValidationErrorNullNotAllowed,Microsoft.PowerShell.Commands.JoinPathCommand

Alguém saberia como resolver isto?