hmm, I think not taking all the photos is not very likely. The interval being randomish could happen if your N900 is doing other stuff at the same time. What could be happening is that you are using a very short interval, and, in that case, it might skip a few photos. Try a longer interval (and with single shots - no HDR or bursts) and see if it still happens. Anyway, I think the latest version of fcamera is out and I'll try to do a new version of TL, soon.