Jitter for Max 5 Auth / Purchase

I am a user running on Mac OS 10.7. I have been using max/MSP since v4.5
and I'm now running 5.1.9 and have only recently needed access to the
jitter family of objects. I am having a very hard time figuring out how to
access Jitter. When I try to use any jitter object I receive the messages:
"Jitter demo period has expired," "Jitter is not authorized," and "could
not allocate object."

I've read the documentation on authorization and I've even re-installed max
5, but I still can't access Jitter. I'm also trying to find in your virtual
shop where I can buy Jitter for Max5, but it says that Jitter comes with
Max 5. So, this makes me suspect that I need to purchase Jitter for my
older Max license. HOWEVER, in trying to download Jitter 1.6, Jitter won't
load because "max version 4.6 or later is required," which is odd because
I'm running 5.1.9.

I am now trying a challenge / response form of authorization, but I'm not
sure how much this will help since I've never owned Jitter and only
upgraded to max 5 years ago without Jitter. I can't figure out how to purchase Jitter through the online shop. Please help.