Paul,

n> Everything works fine with just one client (i.e. one connection to
n> the database). When two clients connect though, the server 'locks'
n> up.

I have been developing something very similar, and looking at similar
problems, but not with 2 threads - more like 100.
What is your database connection string?
It looks like you are using the thread-unfriendly local connection
method.
Ciao
--
Nando Dessena
mailto:nandod@...