Math overflow?

Hi folks I need some help to fix this script - wich I borrowed from PHP and works good with Portuguese strings - Whenever I try the link with some foreign chars it gives me errors: http://www.revistaeletronica.com.br/cgi-bin/encrypt.cgi?texto=dog ---> OK http://www.revistaeletronica.com.br/cgi-bin/encrypt.cgi?texto=cão ---> ERROR Follows the CGI script: #!rebol -cs REBOL[] encrypt: func[frase [string!] key [string!] /local result char keychar][ result: copy "" for i 1 length? frase 1[ char: copy/part at frase i 1 keychar: copy/part at key (i // length? key) 1 char: to-char (to-integer to-char char) + (to-integer to-char keychar) result: join result char ] ] decrypt: func[frase [string!] key [string!] /local result char keychar][ result: copy "" for i 1 length? frase 1[ char: copy/part at frase i 1 keychar: copy/part at key (i // length? key) 1 char: to-char (to-integer to-char char) - (to-integer to-char keychar) result: join result char ] ] cgi-input: make object! decode-cgi system/options/cgi/query-string key: "madeline" pass: encrypt cgi-input/texto key print "content-type: text/html ^/^/" print pass print decrypt pass key TIA -- *:-.,_,.-:*'``'*:-.,_,.-: Carlos Lorenz *:-.,_,.-:*'``'*:-.,_,.-: