How many people/connections are we talking here? Is this app running off a flat database file, with the file on the SME and the app local? This could be a limitation of the application itself not being able to handle XX connections, or your network being overloaded. I've seen some of these take as much as 10Mbps, not that you're limited to 10 people on 10/100Mbps connection, but as you put the more people getting on it will make it unavailable sometimes.