Can you try uninstalling and then reinstalling the NETMF 4.2 and Netduino SDKs?
The error seems to indicate that Visual Basic doesn't understand the NETMF project type.
I uninstalled and reinstalled the NETMF 4.2.
Started C# visual studio 2010. Project loads ok.
Started vb visual studio 2010. The project loads ok.
Reinstalling .NET framework SDK 4.2 did the trick.
ps: It was not my intention to hijack this topic.