Hi eljobe,
I've just talked to my colleague in our TechPubs team who created these installers. The issue appears to be that the 2012 and 2013 integrated documentation sets don't work well together. (I'm guessing our testers didn't test a side-by-side scenario).
If you haven't installed the 2012 documentation then the 2013 docs should install and work fine. You could try uninstalling your 2012 documentation, and also opening your VS help settings and making you you also remove the content, and then install the 2013 docs - but I'm not 100% sure that will clean everything up for you.
Anyway, my colleague will be investigating this, and testing multiple installation scenarios, to make sure he fully understands the cause and will then either tell me how to do a manual fix or will recreate the installer to correctly handle side by side installation of multiple versions. However, I won't remove the 2013 installer from the developer center yet, as my understanding is that it at least works for a clean installation. Sorry for the problem, and sorry that I can't promise when I'll be able to come back here and post a solution.
kintela - It would be helpful if you reposted your last comment in English (as this is an English forum). I tried running it through Google Translate, but the translation to English is clearly incorrect.
Cheers,
Stephen Preston
Autodesk Developer Network