This sounds almost exactly like the problem I'm experiencing -- see my post: Need Help Troubleshooting - Not Receiving/Displaying Messages
I've done everything you have for troubleshooting as well...
I installed the application with Kiwi_Syslog_Server_9.4.1.Freeware.setup.exe. Even though you used the "eval" executable, you got the free version?
EDIT: I uninstalled (again), then installed using Kiwi_Syslog_Server_9.4.1.Eval.setup.exe but have the same problem. Oddly, my previous settings were still intact after the reinstall, even though I'd manually deleted the C:\Program Files (x86)\Syslogd folder.