are you referring to to the clock on my windows desktop?
Yes, a system clock out of sync might cause errors and the wallet will process blocks with the wrong timestamp. It happened to me too

I shut the wallet and compouter down for several hours...Just rebooted it. Wallet is still saying it is out of sync...I must admit. This is frustrating.
Isn't the wallet displaying a message like ""Chekpoint is too old, wait for blockchain to download, or notify developers."?
If so, forget about it. It will work nonetheless.