Mysql 4.1.3-beta stalls when flush privileges

I know that I should use mysqlbug to report bugs, but my mysqlbug prints mysqlbug: problem report sent Description: When there are rows in mysql.columns_priv table query flush privileges stalls when query repeatly. How-To-Repeat: Insert some rows in mysql.columns_priv table. Try

C API mysql_next_result stalls

I know that I should use mysqlbug tool but it doesn't work. Description: MySQL C API mysql_next_result stalls in my program. I'm using pthread and MYSQL handle is using in just one thread. I hacked into the source and found this call is just same as mysql_real_query except it doesn't send query