I am working with both a Panda and MINI FEZ.
I get this error when I try to add a reference (see screen clip)
If I go to the C:\Program Files (x86)\GHI Electronics\GHI NETMF v4.1 SDK\Assemblies\le directory I can get that one to load but when I try to deploy it complains about not being able to copy a file.
GHI just announced new SDK/firmware:
http://www.tinyclr.com/forum/15/2705/#/1/msg26633
I suggest to reinstall SDK and update the firmware.
As your screenshot suggests you have a conflict in file versions. 4.1.3.0 vs 4.1.2821.0
4.1.2821.0 is current version of the .Net Micro Framework.
It hasn’t change for awhile.