Either the actual synth or sample you are using has a very long reverb or your actual samples are overlapping. To stop all sounds, double click on the stop button. It'll kill all sounds that may drag from reverb, etc.
I already got it work just fine.. my quantize settings were a little bit off
actually... there is the same amount of bugs in retail version aswell.. that's why the have software udates
You could be right there, I only recently bought FL 10 when I started releasing music on labels and Ive never had any problems with it compared to the cracked versions.
FL has an issue that when it receives another task (such as changing windows) to complete while currently in the middle of completing a midi command (i.e. playing your recording through a midi "play" command) it doesn't recognize the "midi off" command and so your sound continues to play. Press stop before you press anything else.