CORDBG_E_CLASS_NOT_LOADED (HRESULT: 0x80131303) error with List<double>

I'm creating a List variable. I get this error right when I initialize it like so:

List<double> nums = new List<double>();

Has anyone else encountered this before? I haven't been able to find very much info about his at all. I'm coding in C# using MonoDevelop.

If I switch to Mono runtime in Monodevelop (menu item: "Project / Active Runtime /Mono"), the problem disappears. I created bug report 6124 at bugzilla.xamarin.com. Up to now I'm not aware of any solution / workaround.