In this case (Paccar Financial Corp. v. Potter, Texas Court of Appeals, Fifth District, No. 05-05-00403-CV, October 31, 2007), the individuals who had been corporate officers when a corporation's Texas franchise tax report was due had actually resigned before the corporate debt was incurred after the report was not filed. As a result they were not personally liable for the corporation's debts.
That is somewhat of a surprising result, but good news for the officers. The states have been generally successful in attaching personal liability to corporate officers, but in this case, they were able to escape the pain. Good for them!
It's not necessarily a good thing to be a corporate officer these days. Lots of potential liabilities. As the old saying goes, "you can't know what you don't know".