Hello! Are you working on 4.6 compatibility? We tried to get the latest version (1.5.8 I believe) and it wouldn’t compile. I don’t have the error on hand, but it had to do with a GUIButton function argument not matching. We’re using v1.4.0 at the moment.
The latest NC version 1.5.8 on the asset store works with Unity 4.6 and it includes a couple of GUI tasks as well. I don’t get any compile errors here. Strange. Are you certain it was a NodeCanvas error?