Mistaken trojan block?

Regarding OpalCalc calculator download--

http:// www . skytopia . com/software/opalcalc/opalc_full_install . html

I've used this utility for years.

I was directed to the download page for the full version by the author since I had ended up with a demo in error.

Norton erased the download automatically regarding it a Trojan horse of some sort. I find this very difficult to believe.

I've attached Norton's explanatory screenshot????

Mark