Hi cozyrosy!
One of the first things I would try is making sure that DirectRT-associated files (i.e., your .csv input file, the Stim folder, the Styles.drt file) are all located on the same computer with DirectRT. When I saw you mentioned Dropbox, I thought of some previous cases where DirectRT errors were related to some files located on a service like Dropbox that resolved when the files were all moved to the actual computer.
Also, I would be happy to take a look at your files if you sent me copies; you could either upload them here or send them to me directly at support@empirisoft.com; if you send them to the email, please refer to case 17288 in the message. Please make sure to send me everything that I would need to run this on my own copy of DirectRT.
Jason Reed
Empirisoft Software Support Specialist