problem in UTF-8

[booktoweb]

hello

i want to convert my forum to UTF-8
When used writing these in shell

mysqldump -umysqluser -pmysqlpass --opt database > oldencoding.sql

iconv -f windows-1256 -t utf-8 oldencoding.sql > UTF8database.sql

mysql -umysqluser -pmysqlpass mbdatabase < UTF8database.sql

This problem resulted

Warning: array_keys() [function.array-keys]: The first argument should be an array in /includes/functions.php on line 3699

Warning: Invalid argument supplied for foreach() in /includes/functions.php on line 3699

This line me this way

?�???????�?�?�)

i have backup
How can the conversion to UTF-8

please help