That sucks man. Update the thread with how it goes - I'm interested to see how the state responds to the claim.
Not that I'm a lawyer, but I suspect the state's argument will fall somewhere along the lines of
assumption of risk, in that the mowers (and therefore the State) does not have any [ame="http://en.wikipedia.org/wiki/Duty_of_care"]Duty of care - Wikipedia, the free encyclopedia[/ame].