Employment Law Questions? Ask an Employment Lawyer.
That will depend on the actual basis for the termination.
For example, if the reason that they terminated you is that you didn't follow company policy on the way in which that reporting should be done (and their policy doesn't violate the laws on how errors are supposed to be reported), then the termination would actually be based on violating company policy.
So, it can be a bit complicated actually narrowing down what the actual basis is for a termination.
However, if it can be determined that their basis for termination is really focused more on the fact that you made a report of an error, and it was your legal obligation to make that report, then certainly you can file suit under a concept referred to as "termination in violation of public policy." That is a viable suit in employment law. They problem though is finding an attorney willing to take that sort of claim, because they are not as simple as filing a race discrimination claim, for example. So, it may take some leg work to find an attorney willing to do that sort of claim.