Blog-Pagination doesn't work

HI,

on http://www.rad-touren.at the page-pagination doesn’t work
I see the numbers of Blog-Index-Pages on the end of the page. But if I click on a number of the page, the content of the blog-index.page remains the same, but the number of the page is highlighted.

I did the following things:
* I checked if my customer had put the checkbox for holding the post on the beginning of the page active for all posts. -> No
* I deactived all the plugins, and cleared the page-cache and the browser-cache -> Nothing changed
* I cleared the cache (via FTP) and deleted the caching-plugin -> Nothing changed
* I downgraded the theme from Version 3.4.6 to 3.3.2 -> nothing changed

I don’t know any solution more.
I re-upgraded the theme to the actual version.

Please support me to find the error.

Thanks,
Daniela

I created now an account and post the login data above.

Thanks, Daniela