Heh, and here I thought that was pretty clever naming the UK model gb (great britain, anyone?) ^^. (I may be biased on this though, in France, the term great britain is a tiny bit more widespread than united kingdom, probably because we have the 'little'
britain 
)
Anyway, that does seem to point to a wonky userstore, but we probably can't help much more without logs/shell/serial access... :/.