File can't be opened once special characters are inserted

Hi

I'm been trying to use the note symbols in Special Characters in the Text field to indicate a chord landing on the & of 4. It works fine on the Mac, but if the special character is in the version saved to Dropbox, the error message "File can't be opened" comes up, either trying to open it form Dropbox on either the Mac or the Ipad.

Any suggestions?

Sharon