Invalid string encountered in LETTERS declaration.

Additional Information

The lower-case string has 'X' characters in it, but the upper-case string 'Y' has 'Z' characters.
    or
The format item '%n' cannot appear inside the letters rule.

Recovery

Compilation continues but no compiled source code file will be saved.

Explanation

The letters declaration takes either one string of any size or two strings of the same size after processing. Processing involves changing all the %...# character codes and allowed format items to the single characters they represent. The following format items are not allowed: '%a', '%b', '%c', '%d', '%g', '%i', '%q', '%v', '%x', '%y', '%[', '%]', or '%/'.

[ INDEX ] [ CONCEPTS ] [ TASKS ] [ SYNTAX ] [ LIBRARIES ] [ LEGACY LIBRARIES ] [ ERRORS ]