Have just received my replacement Extreme and getting -101 errors on Google Play.
I searched this, and wasn't convinced by the fixes I found. Most said this was a Google download limit and it would "go away". This I could not accept, as 1) I haven't downloaded anything for over a week while waiting for my replacement Extreme and 2) Why would Google implement such a limit, makes no sense.
I thought about how I set it up, as opposed to the first Extreme, as that worked on Google Play no problem.
I then realised this time, when setting up the tablet, I added a Google Account via Settings->Accounts & sync before accessing the Play Store. This meant that the account details was passed direct to the Play Store. And I was getting -101 errors.
So I removed the Google Account from the tablet and then accessed the Play Store again. This time the store asked for a Google account, which I entered. After completing the "set-up" this way, the Play store worked no problem.
I did notice that when I signed into the Google Play, it defaulted to my.name@gmail.com. Now I have never updated from my @googlemail.com to the @gmail.com so I changed it back to my.name@googlemail.com and it works no problem.
So I assume (and it is an assumption), that when you set up your Account on the Tablet it passes through a @gmail.com email, which is not registered against Play (in my case). Hence stops you downloading.
Hope this helps anyone having the same error....