get-command/show-command error: Object reference not set to an instance of an object

I have started receiving the following error when running either the get-command or show-command commandlets in powershell v3.0

PS U:\> get-command
get-command : Object reference not set to an instance of an object.
At line:1 char:1
+ get-command
+ ~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Get-Command], NullReferenceException
    + FullyQualifiedErrorId : System.NullReferenceException,Microsoft.PowerShell.Commands.GetCommandCommand
 

PS U:\> show-command
get-command : Object reference not set to an instance of an object.
At line:1 char:3
+ @(get-command -CommandType Cmdlet,Function,Script,ExternalScript,Workflow),@(get ...
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Get-Command], NullReferenceException
    + FullyQualifiedErrorId : System.NullReferenceException,Microsoft.PowerShell.Commands.GetCommandCommand

Also, the "Commands" add-on is empty in Powershell ISE, and if I click the "Refresh" button, I receive the error:  Object reference not set to an instance of an object.

Thanks

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Matt