When using Steema TeeChart for MonoTouch (5.4.0) and compile to run on a physical device, I get Error MT2002: Can not resolve reference: System.Void MonoTouch.Foundation.NSTimer::.ctor() (MT2002).
I already know the answer but put the question here as a reference for others.
The problem is that Steema TeeChart uses a bad version of NSTimer, that Xamarin removed in the latest version of MonoTouch.
There is a discussion about the issue here: http://monotouch.2284126.n4.nabble.com/error-MT2002-Can-not-resolve-reference-when-building-for-iPhone-td4656884.html
And a hotfix for it here: https://bugzilla.xamarin.com/show_bug.cgi?id=6987
From MonoTouch 5.4.1, the hotfix will be built in and hotfix installing won't be necessary.