The trial decided the issue of criminal charges, that's all. This woman still owes the taxes. The IRS has recourse to civil process to get that money.
For example: suppose you did business with a crooked partner who stole from you. Even if the guy were acquitted of fraud charges in criminal court, he would still owe you money, money you could collect civilly.
Unlike other entities, the IRS doesn't need a trial, either. It has the power to issue liens for taxes owed, as if it had won a civil judgment. They can-- and probably already are-- garnish her wages, seize property, whatever.
They have already lost this case aganst her once because they couldn't convince a jury that there is an unequivocal statement which requires her to pay taxes. Doesn't that mean that she doesn't have to be expected to pay taxes in the future, also?
The criminal trial did not determine her tax liability. All it did was determine whether she was guilty of the crime of tax evasion. The jury acquitted her of tax evasion, but that jury has no jurisdiction whatsoever over her tax liability. She owes the money, and the trial doesn't change that.