My site is using the iso-8859-1 charset and can't display some of the characters in the toolbar. I have a cheat sheet of the characters that usually cause this problem (often after copying from MS Word) and I took the liberty of searching for them.
Changing to HTML entities (like © and –) or basic ASCII characters should resolve the problem.
Sorry about the long delay. ZFDebug uses UTF8 for character encoding as it solves almost all encoding issues with special characters.