Ok from what I can tell, and im not terribly experienced, is you haven't gone too far astray. Hopefully I can lend some tips from some trouble shooting I went through today.
I believe that this output you get in the terminal has only do with entering something wrong or you being in the wrong directory. I know I copy and pasted a couple of times while doing this and left in the $ before the commands. I think leaving that in will give the same kind of "no such file or directory" error. Now I don't know how, but you might have also gotten out of the directory of android-sdk and its sub-folder, tools that contains adb. I think this could be likely if you left the terminal before/after/during the downloading of the new PG05IMG.zip file and placing it to your SD card. But if you leave terminal anytime just do these 4 commands again, "$ cd .. $ cd .. $ cd and* $ cd tools", same as listed below. The computer not recognizing the ./adb devices command would not have anything to do with incorrectly downloading and saving the new PG05IMG file to your sd card.
Since it sounds like you are trying to start over make sure phone is in debugging and....
you could do a test: (without the $ in front of each line)
$ cd ..
$ cd ..
$ cd and*
$ cd tools
$ ./adb devices
( try this first without the T-bolt plugged in and then again with, just to check if your android-sdk is working as it should )
and if the ./adb command is not recognized when you have no t-bolt in, then you should try re-downloading and installing android-sdk-mac_x86.zip as given in the very first step and start again from there.
if ./adb is recognized without t-bolt as a command but not when it is plugged in, then im just as stumped as you and hopefully a tech wizard will be able to jump in and make good things happen.
Lastly i had trouble with an improperly downloaded pd05img file, so starting over with fresh downloads can make the process seem like a piece o cake again because there hopefully wont be anymore glitches