If you donated by eCheck, according to PayPal it will take 3-5 business days for your subscription to go into effect.

If you donated through normal means, the change is instant if you return back to the site afterwards. If you did not do that, or if there is some server hiccup, it may take an hour for your account to update.

If you did not donate with an eCheck and you still cannot download after 1 day, make a thread here.