Problem: Access denied for user 'root'@'localhost' (using password: NO)

[Hossein Younesi]

Hi everyone,

I'm using mysqlpp on ubuntu 10.04 with mysql 5.1. my program is a multi
threaded one, after each client request it connects to mysql through
mysqlpp, executes some queries and sends the result back to client. So
mysqlpp is used simultaneously between threads. Problem is that when number
of requests increases (more that 10 in a sec) , This error appears:

"Access denied for user 'root'@'localhost' (using password: NO)"

What's wrong? Connection limitation? Executing limitation?

Thanks b4

-- 
Hossein Younesi Vaghar