>>15 There are three possible reasons for that:
1. It contained Japanese or otherwise non-ASCII characters in the password. Check the box 'Restrict key to ASCII characters' in the Tools, Options menu. Some of them may not be a problem, most of them will.
2. It contained # or ! characters within the password. These will start a new secure trip and create a double tripcode, essentially escaping the key.
3. It contained the '&' character. A number of tripcodes I have made contained this character, and they did not work. Apparently, while unlikely, this character can cause problems.
