It has been a very long time since I have participated here, but I came across this thread after having the SDM on a 16-50 go. Thankfully, I was able to make it work again and mostly I just wanted to express those thanks.
I did have some issues, so I will post what worked for me. Likely it was covered somewhere in the hundreds of replies, but I didn't see it. Forgive me if this is a repeat.
First, I don't know why, but I could not get PK Tether to communicate with either my K-5 or my K10D on either my desktop (Win 8/64bit) or on my Laptop (Win 7/64bit). Not sure why but I had no luck.
Fortunately though, and I am sure I found it in this thread somewhere, I was directed to this site:
Debug mode
For the K10D, I made the MODSET.TXT file with the [OPEN_DEBUG_MENU] instruction and put that in the root directory of an SD card. Then, I started the camera with the card door open and the debug mode came up.
Then, I scrolled down until I came to the line saying, `LENS ROM SAVE to FILE` and I clicked on OK for that option. The camera saved a file titled LENSEEP.LNS to the memory card. I then took the card back out of the camera, backed up that file and then opened it with NotePad Plus. From there, I did a find and replace, where I replaced all `C0`text with `80`as was covered by LFLee in #386 of this thread. Then, I put the card, with the new LENSLEEP.LNS file into the camera, left the door open and started up the camera. Then, it was a matter of scrolling to LENS ROM LOAD from FILE and clicking ok. After that, it did take a few minutes, but the operation did finish and I then had auto-focus with the 16-50 again. Works on both my K10D and my K-5, just as it should.
Sorry if this is wordy, but I thought it might be of some interest, just in case others can't get PK Tether to work.
I am very happy and very thankful for the hard work that has obviously gone into this thread.