[TYPO3-install] Install Tool Basic Configuration Error

[Benedikt SChulten]

Hi everyone, i've got a problem with my new typo installation:
The tab "basic configuration" in the install tool of typo3 (newest version of intruduction package) gives the following error, instead of opening:

Fatal error: Call to a member function fetch_object() on a non-object in /customers/e/e/7/********/httpd.www/typo3/sysext/core/Classes/Database/DatabaseConnection.php on line 1294 

I tried to reinstall it twice, but nothing changed, same problem. I googled it, but i found no working solution, so i thought i could ask here, if somebody got an idea.
Many thanks in advance

Benedikt