Currently we only support the IL2CPP scripting backend as mentioned in our Unity Setup Guide (You can search for IL2CPP).
Try building with IL2CPP scripting backend. If you build for .NET then you need to change the sample code to use Task instead of Thread (ifdef using NETFX_CORE macro).
Perhaps someone can help me here.
I'm trying to build the build the extended object tracking from the latest wikitude 8.0 sdk. This is giving me errors. Does someone a solution for me?