starting on after having batterie charged...

Hi!

Some time ago I've noticed that when ever I leave my MacBook Pro to charge on cable, when I start it on again (now having cable disconnected-if that men anything) it reports something like more or less ''you comp. has started again because of a problem..., would you like to report it to Apple...etc''

My question is: what does that mean, and hoy do I eventually fix it?

THANX!!!