Berkshire Hathaway just revealed a record cash hoard.On paper, Warren Buffett looks like he's getting nervous about the stock market. The Oracle of Omaha has long warned against timing the market. But facts are facts. This quarter, Buffett's holding company, Berkshire Hathaway (BRK.A +0.51%)(BRK.B +0.76%), revealed it's holding more cash than it ever has in its entire history -- a sum of more than $380 billion. That's roughly a third of Berkshire's entire market cap.Clearly, Buffett is finding it difficult ...