Thanks Icuk, I've no real idea what i'm doing but I ran ls /home/user/.liqbase/cal in xTerm and the entries were there. Thought I would try another restart before asking for more help and this time the entries were still there! I've no idea why they disappeared last time, all I can think is that I changed the battery, although I don't see why that should have an effect. Having said that, sometimes when I swap batteries I have to input the time and date again, but not everytime!!
It's probably just my N900 gently suggesting a flash.

Thanks again though.

Dan

p.s are you continuing the development of this app? I hope so because it's definately one of my favourites.