Adoptable Page does not exist... (+some questions)

[River cat]

Hello, again.
v.1.3.3
I'm trying to set up adoptables, but after I did some steps, (created adoptable shop, added adoptable to the shop, created common adoptable), I adopted a pet, and when I want to look at them, I got this:

invalid id specified
Adoptable Page does not exist...


May be I did something wrong?

* if adoptable was created with price for shop, but not shop was selected, and (or) was added a promocode to the new adoptable, I got error on the adopt page.

* I still not understand how promocodes works.

*Is there a way (and need) to use old versions without making all wark again? I mean switch to the old one without loosing css, and all settings on the site?
And it's better for now to use which version of mysidia?

*Is it really difficult to make more alternative variations then 2? (Just wondering, if mysidia a going to develop this or I need to learn php or so)

Thank you for your time, and answers!
Best regards, River.