Hypotheses anyone? Likely related to their SSL/Verisign stuff?
It seems to say that a former employee said something that raised questions about the validity of their financial results. Symantec's audit committee is looking into it, and may not be able to file their financial reports when they're supposed to (because they get in worse trouble for statements that they have reason to know are inaccurate than they do for being late).
When this got announced, their stock price crashed 30%. So now some stockholders are suing, because they think the execs should have prevented all this, because the execs' incentives are supposed to be aligned with the shareholders. (The execs' probably should have prevented this. But the rationale for the suit, to me, sounds like "we lost money, so we want to sue, so let's make up a reason". But IANAL...)