There were a couple of things that I added to the script in the latest version. One or both of them may have helped your situation:
1) I added some logic to re-install Superuser.apk if the command that does the initial install of Superuser fails.
2) The original exploit by Dan Rosenberg tries to run the exploit from /storage/rfs0. Based on feedback from several users, the Samba share is not always mounted to that location on the phone, which will cause the exploit to fail when the script attempts to run it. I added logic that will find the 'pwn' executable, and execute it from the proper path.
No, the one that I actually got to work was the version before the latest one....the one with MYGROUP all in caps in the instructions. I really have no idea why the newest one didn't work. I wish I wrote down the line where the newest one failed. Seeing as it took me hours, it most certainly could be a user error. LOL But I saved that 2nd to last version, just in case.