So here's the list of available modules in this directory. As you can see DnsShell is there.  
PS C:\windows\system32> Get-Module -ListAvailable
Directory: C:\windows\system32\WindowsPowerShell\v1.0\Modules
ModuleType Name                                ExportedCommands                                                             
---------- ----                                ----------------                                                             
Manifest   ActiveDirectory                     {Get-ADRootDSE, New-ADObject, Rename-       ADObject, Move-ADObject...}             
Manifest   AppLocker                           {Set-AppLockerPolicy, Get-AppLockerPolicy, Test-AppLockerPolicy, Get-AppLo...
Manifest   BitsTransfer                        {Add-BitsFile, Remove-BitsTransfer, Complete-BitsTransfer, Get-BitsTransfe...
Manifest   CimCmdlets                          {Get-CimAssociatedInstance, Get-CimClass, Get-CimInstance, Get-CimSession...}
Binary     DnsShell                                                                                                         
Script     ISE                                 {New-IseSnippet, Import-IseSnippet, Get-    IseSnippet}                           
Manifest   Microsoft.PowerShell.Diagnostics    {Get-WinEvent, Get-Counter, Import-Counter, Export-Counter...}               
Manifest   Microsoft.PowerShell.Host           {Start-Transcript, Stop-Transcript}                                          
Manifest   Microsoft.PowerShell.Management     {Add-Content, Clear-Content, Clear-  ItemProperty, Join-Path...}               
Manifest   Microsoft.PowerShell.Security       {Get-Acl, Set-Acl, Get-PfxCertificate, Get-Credential...}                    
Manifest   Microsoft.PowerShell.Utility        {Format-List, Format-Custom, Format-Table, Format-Wide...}                   
Manifest   Microsoft.WSMan.Management          {Disable-WSManCredSSP, Enable- WSManCredSSP,   Get-WSManCredSSP, Set-WSManQui...
Script     PSDiagnostics                       {Disable-PSTrace, Disable-   PSWSManCombinedTrace, Disable-WSManTrace, Enable...
Binary     PSScheduledJob                      {New-JobTrigger, Add-JobTrigger, Remove-JobTrigger, Get-JobTrigger...}       
Manifest   PSWorkflow                          {New-PSWorkflowExecutionOption, New-PSWorkflowSession, nwsn}                 
Manifest   PSWorkflowUtility                   Invoke-AsWorkflow                                                            
Manifest   TroubleshootingPack                 {Get-TroubleshootingPack, Invoke-TroubleshootingPack}
When I run the command to Import-Module DnsShell, I get this error and I dont know why..
PS C:\windows\system32> Import-Module DnsShell
Import-Module : Could not load file or assembly 
'file:///C:\windows\system32\WindowsPowerShell\v1.0\Modules\DnsShell\DnsShell.dll' or    one of its dependencies. Operation is 
not supported. (Exception from HRESULT: 0x80131515)
At line:1 char:1
+ Import-Module DnsShell
+ ~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (:) [Import-Module], FileLoadException
+ FullyQualifiedErrorId : System.IO.FileLoadException,Microsoft.PowerShell.Commands.ImportModuleCommand
Note: I would have posted pictures but I needed a rep of at least 10 in serverfault
 runcmd
 runcmdLook at the file properties on DnsShell.dll and see if, on the general tab, you see an Unblock button at the bottom. This can happen if you download the files from a remote source.
This is due to the version of PowerShell you are running. This module runs with 2.0 ONLY. If you are getting the error run 2.0 by running "powershell.exe -version 2.0" Then import the module.
Download module from: http://dnsshell.codeplex.com/
1- Extract DnsShell.zip to one of the paths shown by $Env:PSModulePath
2- Run: Import-Module DnsShell
For me only works doing this:
If unblocking with the Explorer doesn't work or if you have many files to unblock, you can remove alternate data streams with the streams.exe Windows Sysinternals tool located at https://technet.microsoft.com/fr-fr/sysinternals/streams.aspx.
streams -s -d DNSSHELL_DIRECTORY
This command will remove every alternate data stream in the DNSSHELL_DIRECTORY files and all of its subdirectories. So don't use it on random parts of the filesystem.
To be sure, you can first list the streams with:
streams -s DNSSHELL_DIRECTORY
 Christophe Drevet-Droguet
 Christophe Drevet-DroguetUser contributions licensed under CC BY-SA 3.0