I found the problem and solution. After installing PMB on the second computer, I connected the camcorder to the computer and it started recognizing the m2ts files. At the end of the installation of PMB, there was a message saying "Once your camcorder is connected, more device specific features will be installed" or something to that effect. I did not imagine that would include enabling PMB actually to see the existing m2ts files. Anyway, it works now. Another weird Sony thing. What if the camcorder is gone (sold, broken, etc) and I want to install/use PMB on a new computer?