@jetdv Not sure if this will help at all, but I tried the other scripts in Excalibur and they work. Only the multicam is malfunctioning. I see there is a similar post from 2017 on your jetdv site from someone else. I've opened older versions of the software where to see if it is also happening in 15 and even 12. It is. So whatever the illness it is universal and not limited to 16.
One thing you might try... the folder with the image file, copy the folder UP one directory level. It does not make sense but I have had one other person tell me that fixed the same issue even though it works fine on my machine without doing that.
I'm still not sure why that is the solution as the code says to look in the sub-folder and it is properly working on most machines. I've only heard of a couple of instances where this is needed. Glad to hear it worked for you.