Unable to connect to any of the specified MySQL hosts (no replies)

Hi everyone

I am developing a windows service using C#, .net 3.5, visual studio 2008 sp1. I am using the .net connector 6.2.2. I am connecting to mysql server 5.1.49-community for Win32. This database server is running on a Windows 2003 enterprise sp2, and the service is place on the windows 2003 server, too.

As I am running a test program to testing con-currency of the windows service, the log file records "Unable to connect to any of the specified MySQL hosts" when executing non-query operations. But it looks right when the service just started and run several few non-query operations.

As I run query "show global status like '%conn%'" in Navicat, it shows:

Aborted_connects 1
Connections 95
Max_used_connections 16
Ssl_client_connects 0
Ssl_connect_renegotiates 0
Ssl_finished_connects 0
Threads_connected 10

I supposed there was something wrong with my MySQL connector. But when I take the windows service to run on Windows 7, and run the testing program again, the error "Unable to connect to any of the specified MySQL hosts" will never happen.

So strange, how could it be?

Thanks!