The timing is a bit off for this song - it's OK at the beginning but really goes afterwards, which indicates the BPM is not correct. A bit of fiddling and adjustment should fix this - just make sure the timing ticker is still in time at the end of the song as well as the beginning.
Also, you don't seem to have used beat snapping, which is why Lumino thought some of the notes were off. I'd suggest fixing the timing, and then using Timing-->Resnap all Notes. After resnapping the notes, the notes may still require some nudging to get them in time - just play the song in edit mode and listen carefully.
As Lumino suggested, try implementing breaks where there are large gaps between notes - this option should be available soon.
Good first time effort!
eyupz
