install.php failed

i got a error page while install at step 3…
after debug the prog. i found ./wp-includes/wp-db.php has some problem… I don’t know why, but mysql_fetch_field don’t work in my server….
ORG:
while ($i < @mysql_num_fields($this->result)) {
$this->col_info[$i] = @mysql_fetch_field($this->result);
$i++;
}
$num_rows = 0;
while ( $row = @mysql_fetch_object($this->result) ) {
$this->last_result[$num_rows] = $row;
$num_rows++;
}
CHANGETO:
while ($i < @mysql_num_fields($this->result)) {
$this->col_info[$i] = @mysql_fetch_assoc($this->result);
$i++;
}
$num_rows = 0;
$this->result = @mysql_query($query,$this->dbh);
while ( $row = @mysql_fetch_object($this->result) ) {
$this->last_result[$num_rows] = $row;
$num_rows++;
}
then the bug fixed.