If you are still stuck send me an e-mail , but it is very unlikely that the code is invalid. The code worked last time I installed Thumber, but not this time. If a code worked once, it will always work. If you can't get your original code to work, chances are good that a new one won't help either. I recently registered and paid for my copy of Thumber.
All updates are free for registered users.
Your registration code will work for all future releases. Only the freely available documents I've picked up off the internet. Wotsit has some general stuff about JPEG files. Other than this, there is no difference. For a long time, there was no freely available documentation on the EXIF format.