Emacs: AUCTeX-LaTeX compilation error

I have been using LaTeX with Emacs and AUCTeX for 2 years and I haven't run into any problem. However, yesterday when I tried to compile the master file LaTeX gave m开发者_如何学Goe a strange error:

ERROR: Package inputenc Error: Unicode char \u8:\303\lst@FillFixed@ not set up for use

--- TeX said --- with LaTeX.

See the inputenc package documentation for explanation. Type H for immediate help. ...

l.963 magicamente, è ancora intatto. È una struttura solidamente costruita

I think the problem is the encoding format (è È) but I don't understand why this problem happens only for one "subordinated" file and not for the others.

The encoding I use is UTF-8 and is set both in my .emacs file and in the LaTeX master file. Moreover, the mode line says U, which indicates UTF-8 is used as an encoding for the buffer.

Do you have any suggestions for resolving my problem?

If that 303 is supposed to be the unicode point for è or È, then I think something is wrong. It should be 232 (0xE8) resp. 200 (0xC8). Have you tried re-entering those characters?

Have you tried

\usepackage[utf8]{inputenc}

That has some limitations - see Icelandic, utf8 and utf8x in LaTeX