Found this from doing my own research! Either way epic failure by Toys R Us who should issue an apology and provide some sort of compensation for this inexcusable issue at the worst possible time!.....
I was just able to register and setup parental control from desktop browser after more than 2 hours trying different approaches. I then used that account info to login into tablet and activate controls. Here is what I did step by step.
1. When you try to activate your tablet it open page at this URL: (you might have to restart process couple times - site seems to loose info enetered in previous step)
You will have to replace guid value 0099FXFX7X00-0 with the actual value of your tabled ID - you should be able to see it in browser address bar.
2. Complete 4 step account setup wizard - in last step when it asks for "Child's firstname" enter unique Id there something like JoeDoe2009 - there seems to be some issues with unique names for app because when I enter my sons name it said it was already taken.
3. After Child's name was registered you will be redirected to payment page - you will have to enter Credit card payment info for $1 transaction (text says that you will be reimbursed for that later).
4. You should see page saying tablet was registered and You should receive email with your Id and password in clear text to email you used for registration.
5. Go back to tabled and tap on MobileParentalFilter icon (one that looks like flower) -- you will see registration wizard again -- on the bottom there is a link saying "ALREADY GOT ACCOUNT" - enter your email ID and password there - you will be taken to parental filter activation on tablet and all should be set.
That's it. Again be ready to restart this process from any point all over again because site is very slow and seems to loose your session.