It's a safety feature built in when HB/GB/WoW crashes. Just change your computers clock forward one hour, open HB/GB and the change it back to normal. It's an inconvenience but I'd rather have it than get banned.
There have been severals posts about that. Always learn to use forum search for example.. I founded for you: http://www.buddyforum.de/showthread...s-before-trying-again.&highlight=warden+check