Update: Got it working. Backing up in Titanium as I write this.
Was a little weird during the process. Change connection mode to Windows media sync after the above "permission denied" debacle. Doing this booted me out of the shell, so I re-did all the steps. got a weird "text file busy" message when executing "cp /sdcard/busybox /system/bin/busybox". Tried it a few times with the same result and decided to say **** it and continue following the instructions.
Long story short, I have root. Why the **** does every individual phone seem to require tweaking to the steps in order for this to be successful? Bizarre. I know why Windows machines with different hardware and drivers and whatnot require tweaking and I'm pretty good at that, but we all have the same damn hardware on the X, do we not?
Anyway, try the above if you're having trouble.