Another one bites the dust: This time it was Engineering Animation (EAII:Nasdaq), a software company that makes so-called visual-process software used by automotive, aerospace and other types of manufacturers. Its stock tumbled 18 1/4, or 46%, to 21 11/16, after the Iowa company warned that its first quarter would miss analysts' estimates -- and miss them by a long shot. It blamed an inability to close several sales that it thought were in the bag. That's not good for a company that loved to brag how it had beaten the Street for 12 straight quarters; its CEO, in fact, was quoted by Dow Jones on March 26 as saying he was confident the company would meet its estimates for the year. The company says it's sticking with its guidance for the final three quarters of the year, but several of its biggest fans in the brokerage industry aren't buying it. Piper Jaffray, for example, cut its first-quarter estimate to 4 cents per share from 26 cents, while downgrading the stock to a neutral from a strong buy. (The analyst, Hany Nada, didn't even stop at buy, a sign of how miffed he was.)Yet this was just the latest in a string of companies that short-sellers had been hammering on charges of aggressive accounting. Never mind EAII's recent restatement, after discussions with the SEC, of overzealous in-process R&D charges. Back in February, Marc Cohodes of Rocker Partners, one of this column's regulars, was quoted here with a laundry list of reasons he thought it was only a matter of time before the company went kaplooee. (He remains short the stock.) Two key items were unbilled receivables and a negative cash flow. Unbilled receivables occur when a company books revenue on a product that has been shipped without sending out a bill. And since when does a software company have negative cash flow? Not often, which is why Cohodes, whose recent hits include the blowup of Network Associates (NETA:Nasdaq), had zeroed in on Engineering Animation. "When you do this long enough you see tendencies," he said yesterday. "In the late '80s and early '90s it used to be the use of capitalizing software development costs.Now many of those companies (like Media Vision, Knowledgeware and Frame Technology) were either acquired at low levels or they're out of business. In the late '90s it's in-process R&D, which is getting rectified, and unbilled receivables. "When you see these they're not a yellow flag. They're not a red flag. They're a black flag. And this company has been playing with unbilled receivables for many quarters. And they've had negative cash flow for more than a year. "The difficult part about being short names like this is that guys who own the stock make up various stories, and the whole deal with these stocks has been to squeeze the shorts."A short squeeze is when the owners of shares borrowed and resold by short-sellers demand the shares be returned to their rightful owners. The shorts are forced to buy the stock, an event that can cause a stock to rise rapidly. "And when that happens," Cohodes says, "nobody wants to focus on the real issues. This company had real issues, has real issues and will continue to have real issues."One of those issues is that much of Engineering Animation's business is done toward the end of the quarter. Witness the impact of just a few sales not getting completed. "There were 365 days in the year, and 90 days in the quarter," Cohodes says. "If you're in a business that depends on the last week for your sales, you're in one horrible business."