Steam suxs!!!!!!!!!!!!!!!!!!!!!!!!

[el0375]

To me happens if i am happen to be offline, before putting steam in offline mode. only way is to have internet for that time. It may be that if you put it on a different machine, steam detects its a ''different pc'' so sends you a confirmation code, type it right and you should be fine.
apart these, i dont know what else it can be, perhaps go to steam support forums
i hope that your problem will be resolved.