GoLang, Walk GUI and IntelliJ IDEA 2016.3.2

 Hi, I am new to the three items in the subject field. I am using IntelliJ IDEA 2016.3.2 to code a small Golang app which uses the Github rep " github.com/lxn/walk", which is a Windows GUI.

I have tried for days to get rid of the following error:

In have reinstalled IntelliJ IDEA 2016.3.2, the Golang plugin, deleted and re-downloaded the Github rep and various other actions without success.

Any help would be appreciated.

Lawrence