Seeing that no one had yet responded to your post, I though I would take a look at your issue and see what was involved.
Unfortunately, the addon you linked to in your post clearly states that it requires version 1.5 BETA1 of pixelpost and the only version offered from the page you linked is 1.4.
That said, it doesn’t look to be that difficult to install, but I will have to download the correct version, and you will have to have the correct version installed for it to have any chance of working without possible programming changes.
What version of pixelpost do you currently have installed. I was only able to find version 1.5 at the “new website” (man, their site is messed up - two different versions of the site intermingled - if one follows your link).
I’m not looking for any money, and I would take a look at it for you and see if I can help you get it installed, but that isn’t possible without the correct version of pixelpost.