Mysterious unidentified error message
I'm not sure, but it looks suspicious. Poorly written, use of exclamation mark, reference to "PC" - it all looks weird. It's pretty useless too - you get an "OK" button and nothing else? What sort of dialog is that?!

Maybe check your date/time settings, but if there's no problem, I'd be a bit concerned about malware. Did you install any software recently?