Error with script-loader.php

Hi,

when i try to start the /install.php, i’m getting always the same error:

Warning: require() [function.require]: Unable to access /var/www/webXXX/html/wp/wp-includes/class.wp-scripts.php in /var/www/webXXX/html/wp/wp-includes/script-loader.php on line 28

Warning: require(/var/www/web111/html/wp/wp-includes/class.wp-scripts.php) [function.require]: failed to open stream: No such file or directory in /var/www/webXXX/html/wp/wp-includes/script-loader.php on line 28

I tried it on 3 (!) different Webspaces and checked everything a hundred times… always the same error.

thx and best regards!