Hello,
If I import Noesisgui first then FlowCanvas, I will get these errors:
Assets/NoesisGUI/Plugins/API/Proxies/LineBreak.cs(18,26): error CS0246: The type or namespace name `Inline' could not be found. Are you missing an assembly reference?
Assets/NoesisGUI/Plugins/API/Proxies/Span.cs(33,29): error CS0115: `Noesis.Span.CreateCPtr(System.Type, out bool)' is marked as an override but no suitable method found to override

Versions:
Unity3d 2017.1
Noesisgui 2.0.2f2
FlowCanvas v1.3.2

Finally, I find that noesisgui is not compatible with unity3d 2017.1 not FlowCanvas.

Latest version is compatible with Unity 2017.1 but not yet with the new Mono/.NET 4.6.1 runtime. We are working on in. Thanks for your patience.