ios 4.1 is afflicted by a very annoying bug:
with the change from DST to the standard time the repetitive alarms doesn't work fine.
You need to move your repetitive alarms 1 hour before.
It seems that Apple will solve this annoying bug with version 4.2 of the iOS. Anyway on the 7th of November when the standard time will be applied in the USA the bug will be solved.
The above map (http://it.wikipedia.org/wiki/File:DaylightSaving-World-Subdivisions.png) shows the nations that are currently using the DST.
Gg1