I hope this post isn't already present somewhere in the forums, if so, I'm very sorry for disturbing with an already answered question.

The problem is I can't download the guitar pro tablature for Black Dog (from the guitar tabs section of this website); but all the other songs I looked for (like fool for your loving from white snake) do work.

The messagge which appears is the following:

This tablature contains content from a third party publisher and has
been blocked by the Music Publishers Association in your country.

This is for all the 4 or 5 versions of the song tablature in guitar pro format.
Can somebody help me with this? Maybe send it via e-mail?

I think you just need to search elsewhere from the internet. And give some time for it, since most of the Zeppelin tabs I've come up with have been blocked.
You can work around it by going to the URL via a proxy web site. E.g. proxify.com worked for me.