Sleeping threads even with wait_timeout on Server2003/XP

Hello All,

Currently we are running MySQL 4.0.17-nt on a Server 2003 machine. I
am having a problem with connections hanging around in a sleep state,
and building up over time. Eventually websites start returning a "No
More Connections" error. Our websites are ASP.NET, and we are using
the CoreLab MySQLDirect.NET component for the .NET interface. Our code
opens and closes each connection explicitly using that API, but
occasionally ASP.NET worker processes start a new thread and one of
the connections (persistent and pooled I assume) is sleeping and never
appears to be reused. This happens over time until there are alot of
them. I thought that setting wait_timeout to a reasonable value, say,
20 minutes, would help clear up those unused connections, but it
appears to have no effect. Time counts on the threads in the process
list just continue forever.

Anyone have any insights?

Thanks,
D. Niemeyer
Xionetic Technologies, Inc.