Ya, that's a 100 error, which is your Internet connection.
Download Pingzapper (free trial), and use it to tunnel psobb.exe. Set it for stability and select a server that is closest to your location. If you are still having 100 errors, then you may need to buy a new ethernet cable (damaged ones cause crazy ping (ping is bad)) or readjust your internet set up to get a better signal.
Fortunately there are a number of straightforward fixes to solve this issue. Unfortunately it is hard to know which one will do it. Have patience and keep coming back for help, and you will be playing again in no time.