Problem with moving dots movies on online experiments

With that link the experiment runs until it gets to the first trial where I get the error

TypeError: Cannot assign to read only property ‘undefined’ of object ‘#’

which refers to the line: psychoJS.importAttributes(trials.getCurrentTrial());

As per my crib sheet, you may have blank columns in one of your conditions files [dvbridges] e.g., Unknown resource, conditions file

So, please could you upload your conditions file here?