(This would also be true for CRA's NetFile service, which is still open, just, for 2013 returns).
You will have to wait a couple of weeks patiently until Turbotax 2014 on-line is CRA certified, then you can use the on-line service for 2014 tax year and your prepayment code. Staples is jumping the gun, to no useful purpose.
Check your product packaging again, as it may not be an activation for a download. It be similar to a prepayment card for filing after you complete your tax return.
Also note this information on the website. You might be a bit early.
"TurboTax Online 2014 is coming in mid-January!"