Plugin Error

I just got the Galv plugin for diagonal movement and I got the error TyprError Cannot read property 'length' of undefined.

What does this mean and how can I fix the issue?

(For reference I also have plugins from Yanfly Engine Plugins and SumRndmDde)

I just got the Galv plugin for diagonal movement and I got the error TyprError Cannot read property 'length' of undefined.

What does this mean and how can I fix the issue?

(For reference I also have plugins from Yanfly Engine Plugins and SumRndmDde)