After much discussion, help from Dan Gonzalez and many others...
We figured out why many cannot locate the freepack Polybius in their Cakewalk accouont.
 
It could be waaay down your list, at the date you first obtained Z3TA+2... on my account the freepack link was waay down the list right below the original download link for Z3TA+2...
 
I hope this helps you....

+1

Still not seeing it. I got Z3TA+2 as part of the X1 Production Suite, does that mean I don't qualify because I didn't buy it separately or something? 

sharke
Still not seeing it. I got Z3TA+2 as part of the X1 Production Suite, does that mean I don't qualify because I didn't buy it separately or something? 

I doubt it. My copy of Z3TA+2 came with the "First-Class upgrade to Production Suite" X1 promotion I purchased on 25 Jun 2012. The "Free Polybius Expansion Pack for Z3TA 2" line item was added to my account yesterday before the first post on the forum about it. It carries the same date at the promo purchase.
 

sccok got it!
Sharke ...please do a follow up post if you still don't see it.
I had to hunt for it but it was waaaay down there with my first listed acquisition of Z3TA+2
So far... I read through about 8 of the same suggestion and finally had to comb through the list of purchases to find it.
 
It seems to be really cool freebie from Cakewalk.
 
Let us know if you still can't find it after a thorough search ...the listing is date sensitive which means if the original acquisition date was 010112 ...then you  can find the freebie link down there with the original purchase...

sharke
Still not seeing it. I got Z3TA+2 as part of the X1 Production Suite, does that mean I don't qualify because I didn't buy it separately or something? 

Hey sharke, I was in the same situation as you.  If you PM Dan he'll fix you up with the sounds.  Send him your serial number which you can get by clicking on the z3ta logo.
 
The sounds are great !  Gotta compose a song "Ode to the 1980's video game".
 
As most z3ta programs, these are loud so be careful with your ears.
 

There are also some C64 SID emulation VSTi's available for free if you hunt around. A lot more work than using these ready made sounds of course, but doubtlessly fun to play with. I had great fun with the SID chip when I was a kid. It was my introduction to ADSR envelopes. You could squeeze so much music out of those babies. My musical hero back in those days was Rob Hubbard who was the star of the C64 game music world. That guy was a trailblazing genius. You can listen to a lot of his music on YouTube, my favorite is the theme to One Man And His Droid. 
 
Ceephax Acid Crew did a song called Arcadian which is a tribute to 80's game music complete with 8-bit sound effects, I love the soaring lead in it and the chiptune chords which were all the rage back in the day. It's on YouTube no doubt. 

Hmmm that was basically what I posted on the first thread ages ago.
The store really needs an option to sort by the latest plugins added.
 
Here's a browser tip... CTRL + F

"How to Download Polybius: If you already purchased Z3TA+ 2, you can download the free Polybius Sound Pack from your page on the Cakewalk Store.  If you have not yet , you will need to use the same email address as your Z3TA+ 2 registration. Then proceed to the section and under “My Registered Products” you will see the Free Polybius Expansion Pack for Z3TA+ 2."
 
A little late to the party, I just learned about this promotion today.  Like some others before me, I am unable to find the link for the free sound pack in My Account section.  I invoked the "Find On Page" search option in my browser just to make sure the link wasn't hiding in plain sight, but no "Polybius" found.  How did other folks finally resolve this?

By contacting Cakewalk support or a PM to cakewalk staff.