Every place I have looked, it appears as though Michael Tapes is not in business any longer. He used to have a Facebook page. My search was certainly not exhaustive, so he may be out there somewhere.
But, you really do not need the software to use his targets. You only need to determine if a given lens focuses in the same place on the sensor & in the viewfinder
You can even do it this way: mount a yardstick at a 45 degree angle, mount a focus target (like a playing card) Next to the 18" mark. Focus on the card from about 10 feet away. When you view the file on your computer, if the numbers lower than 18 are sharper than the card, you have front focus, if the higher numbers are sharper than the card you have back focus. If needed, make an adjustment and take another shot.
That's all you have to do. Use a tripod and lots of light so pix will be sharp.
There was really no need for the target or the software, other than perhaps ease of use.
But front/ back focus is not complicated
Should you find that none of the pictures are dead sharp, there are only two possible causes ....movement/vibration (re do the test with more light / better tripod, or the lens may need adjustment.

My point here is if you can't find your software key AND your software, you can replicate it easily at zero cost.