Is there a limit to how long a wallet can be offline? I have a wallet file I backed up June 2011, and has been offline for over a year now. When I copied it back into where the files are stored with the official client, it says my balance is 0, with no transactions.

Does it take a long time for my balance &amp; transactions to get updated correctly, or is my wallet considered corrupted, and the coins lost forever?
Any unspent bitcoins against addresses in your old wallet should be retrievable.

The client won't show transactions that haven't been downloaded to your copy of the blockchain yet. There should be an icon in the lower right corner of the Bitcoin-QT client that indicates progress on downloading the blockchain. It can take a few hours (there's around 2.5GB to download, and it downloads them slower than you'd expect because the client verifies the blocks as it goes).