Make sure the S-89's are named correctly. I think esp. the 4up may need renaming to the old format. (the correct names would be S-89-?.jpg for the single and S-89_mu-?.jpg, where ? is an alphanumerical string, used to identify a language. For English E is typically used, but anything would do)
Also make sure the template folder only holds the jpg not the pdf or other clutter: TB may default to a problematic file before you can even choose the template you need. (speaking of which: do not define TB's default template folder as your custom template folder. If you do want that, you would have to change that default folder's permissions).
If necessary we can do a screen sharing session. I am at CEST (GMT+2). We'd have to find a way to get in touch as direct messaging is no longer working here.