Strangely, I've found PMB won't even access .MTS files copied via USB from the camcorder to the computer.
All you get is (x) icons when you try and associate a folder on your machine with AVCHD files in it that you copied off.
Oddly PMB works fine with .mpg files, doing face recognition and thumbnails.
Stupid that it won't work with the actual native .MTS files, which surely is the whole point of the software, and also the whole point of a "associate folder for use with PMB" icon.
I guess you have to copy the files from the camcorder via PMB rather than the OS via Windows Explorer!
Sony software is rubbish by the looks of things. Shame they make such good camcorders, I've always avoided them for their "proprietory" and non-standard approach to everything over the years.
Another approach is to use Premier Pro, but you'll need the AC3 codec from the Encore Installation and the MainConcept MPEG Pro 3.1 HD plug in to see/import your Sony's AVCHD files. Google for the software and you'll find it.
For previewing the files in Windows, the latest build of VLC player 0.9.6 supports AVCHD finally, but its a little buggy at the moment, and sometimes freezes while scrubbing towards the end of large files.