I got a Windows Server 2008 with WTS installed to a lot of people use.
But sometimes spark do some kind of “bug” or “problem”.
Some people cant see their messages and cant receive messages. They type everything, press enter, it actually sends, but doesnt show on their screen, and if the other person replys they cant see either.
Have you tried another client on your WTS? Maybe another client doesn’t have this issue, that means your server works correctly. If you have the same issue with another client like pidgin or miranda then you have to check your server configuration.