in 1and1’s FAQ’s… there something about making your server space use the .php5 extension [ which is what your problem is ].
I had the same thing with 2.7 because the auto-updates require php5 and 1and1 won’t work w/o editing the server php variables or whatever it is.
Create a .htaccess file and place the following line AddType x-mapp-php5 .php in it.
This will tell Apache to use PHP 5 instead of PHP 4 for the extension .php in the
directory the .htaccess is placed and all sub-directories under it.
You can use AddHandler x-mapp-php5 .php as an alternative for or instead of
AddType x-mapp-php5 .php
This one might help [ https://faq.1and1.com/scripting_languages_supported/php/9.html ]
