image not found in Experiment Builder

Question

I'm using Experiment Builder to code an eye-tracking experiment, where I keep running into this error where the experiment terminates itself right after the first trial. It would report the error "File does not exist: runtime/images/6785105752414573539.png". However, after looking at the imagelst file auto-generated by Experiment Builder, it's not even the corresponding image number of the actual first trial. I thought this was really weird and spent forever debugging, but haven't made any progress yet.

Things I've tried: -Running a different list -Cleaning and test running -Changing column names

Would appreciate any suggestion and help! Thanks a lot!