TypeError: Cannot read property '0' of undefined (ImageStim and Scheduler)

URL of experiment: https://gitlab.pavlovia.org/andrewra/exploitexplore/blob/master/exploitexplore.js

Description of the problem:
I’m hitting error after error trying to get this experiment working online… This one seems to be several instances of undefined parameters.
The actual errors seem to be around ImageStim and Scheduler.

EDIT: I see previous posts have been remedied by adding a size for images but all of mine have size values. And another warning says mask is undefinied but all images have attribute None

Solved this error by unticking Istrials box in my blocks loop.