A couple of things
- TempPathbameCreator will only work when it is run, so if using partial runs of the workspace you'll need to create the temp folder, download to it and read it in the same run because the temp location will be cleaned up after each run.
- to debug this kind of headbanging issue, what I usually do is to put in a Decelerator (with some time like 9999 seconds per feature) after putting something inside the temp location or after creating the location. The decelerator will prevent the temp location from getting deleted so you can go and find the downloaded file to make sure it is as you expected. Usually you can get the path of the folder from the log file but you may need to put in a Logger somewhere.
Hopefully one of these should point you in the right direction to solve the problem.