Weird error: InstantiateT() cannot be called if T is an abstract type

[wim (Wim Dekeyser)]

Hi Pei Chin - also see this post by @Dani_Abalde:

Grasshopper error message

Some of your installed plugins fail to load, try uninstalling the most recent ones until the message disappears and contact the developer when you discover which plugin it is.

-wim