TypeLoadException - need help with loader log

I have a CF project that has been working for quite a while. Recently, I began doing unit testing of some CF assemblies from a desktop targeted project. For some reason, the code no longer runs on the device. It gives the following exception:

Could not load type 'System.Collections.Generic.List`1' from assembly 'mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=969DB8053D3322AC'.

I'm not sure if I've somehow used generics in a way thats not supported on the CF but yet is still allowed to be compiled (since it runs from the desktop unit test projects). I have no idea what's going on. I've tried reinstallation of .NET CF 2.0 SP1.

Here's a portion of the output of the loader log:

========================================
Process [\Program Files\Test\Test.exe]
ProcessID [0xeea243aa]
Date [2007/01/09] (yyyy/mm/dd)
Time [21:29:13] (hh:mm:ss)
NETCF [2.0.6129.00]
Platform [Windows CE v5.1.70 (PocketPC) WinCE5ARMV4I release V2\SP1 ARMV4I IJITv2]
========================================
GAC: Updating GAC [0x0]
GAC: Checking .gac files inside [\Windows\]
GAC: Found [Microsoft .NET CF 2.0.GAC] .gac file.
GAC: Found [System.SR.2.0.ENU.gac] .gac file.
GAC: Done with the file system check. Checking the registry.
GAC: Found [System.SR.2.0.ENU.gac] registry entry.
GAC: Found [Microsoft .NET CF 2.0.GAC] registry entry.
GAC: Done with the registry check. Let's compare.
GAC: Entry [System.SR.2.0.ENU.gac] is up to date.
GAC: Entry [Microsoft .NET CF 2.0.GAC] is up to date.
GAC: GAC is up to date.
Compatibility mode [2.0.0.0]

...

Missing Type. Class [System.Collections.Generic.Dictionary`2], Assembly [mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=969DB8053D3322AC].
Missing Type. Class [System.Collections.Generic.List`1], Assembly [mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=969DB8053D3322AC].
Missing Type. Class [System.Nullable`1], Assembly [mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=969DB8053D3322AC].
Missing Type. Class [System.Nullable`1], Assembly [mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=969DB8053D3322AC].
Missing Type. Class [System.Collections.Generic.List`1], Assembly [mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=969DB8053D3322AC].