Well, I uninstalled Qtlockscreen for a very severe bug.
Apparently, Qtlockscreen conflicts with alarms, i.e. it is 6:29 A.M, alarm set to 6:30, phone is locked, once the clock hits 6:30, the alarm goes out, but after a few seconds Qtlockscreen appears followed immediately by the hildon lockscreen and the alarm turns off. So this renders the alarm unusable as it shouts for a few seconds only, not enough to wake me up...
@ammyt : not complete but something relating to your problem is at my side .
the alarm went fine , pressed stop and again screen got lock , but when i pressed the power button to unlock , the default slide to unlock screen appeared , slided and then locked my screen and the next time pressed the power button , qtlockscreen appeared .