Commented Unassigned: Input string was not in a correct format [3609]

I have upgrade to the latest NuGet version 2.7, and I now get the following error when trying to install a package. I am running on VS2012 Ultimate. I had all of the latest updateds installed. I did just install an update to VS for I believe the Windows Phone 8 that was in the extensions list. I also just installed the latest version of Typescript.

PM> install-package log4net
Installing 'log4net 2.0.0'.
Successfully installed 'log4net 2.0.0'.
Adding 'log4net 2.0.0' to Tyson.OperatorUpload.
Install failed. Rolling back...
install-package : Input string was not in a correct format.
At line:1 char:1
+ install-package log4net
+ ~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [Install-Package], FormatException
+ FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand

PM>
Comments: @JeffHandley - I don't believe that I had a pre-release version of VS2012, but I can't say for sure.