Migone:
I'm guessing that you've already solved this issue, but since I don't see a resolved comment or thanks for solution etc. here's a little something just in case you haven't or should someone else run into this problem.
Condition: It looks like you've somehow (perhaps inadvertently) created a predefined value without a language key translation.
Solution: Create Language Key for System translation.
- Go to Settings - Language Settings - Add Key (under keys menu in upper right corner)
- After clicking Add Key button paste your untranslated system string _adm_txt_mp_other in Key Name field of popup dialogue window
- Leave Category as System
- Under String Text For Language enter what you'd like that text say (in your case probably other)
Once you save you'll have created a new language key to go along with the current system string. Key name "other" will now display in place of "_adm_txt_mp_other" and no, they do not have admin access.
Just came across this unanswered question and wanted to add a little input to help the next user.
Hope it helps
DivineArc