One more thought - it's a longshot but, what's your system's language setting? While I seriously doubt that'd be the problem, I don't think we can say for sure NeoLemmix works on every possible language setting. Off the top of my head, we have or have had people here who use English (both US and UK), German and Finnish; and most likely a few others too. If yours isn't one of those, can you (if you don't mind) try changing to one of them and seeing if it works; and if it does, can you let me know what your usual language setting is so I can try and investigate why it doesn't work?
By the way, I moved this topic to the NeoLemmix board, as it's more likely NeoLemmix followers will see it there, in case anyone else has had similar problems and knows of a fix.