I have checked the form with ODK - XLSForm Online v2.x. I don’t think that is the problem. I am using two CSV files. One of them is giving the error, but why that is, I don’t know. I already have used these CSV files in another project, and there it worked properly. Could you assist me to fix this problem?
When having a closer look at your xlsform, I see that you are using some column header (like calculate which should be calculation) that is not compatible with the system:
Fix this and also validate it through this online validator which should help you identify syntax issues.
Besides, I also observed that you are tying to use the select_one_from_file question type. Maybe you could learn more on the same through our support article Select One or Many From External File Question Type.