any complete instructions on touch probe setup?

Yes, JP5 (input pullups) is closed, and both power LEDs are lit. When I suggested that pin 15 was not special, I meant in the sense that the "net probe" command for it was no different from that for pins 10, 11, 12, or 13, except for the pin number.

You might want to check if your parallel port cable is good. You could also use a meter to check if the voltage on pin 13 on the DB25 connector on the BOB changes when you test pin 13 input.
If there is no change on the DB25 and everything is set correctly it would appear the isolator is bad.
As you pointed out it does test good on pin 15 which does not go through the isolator.

Rick G