[Hans]

Make sure you have the following lines at the end of your suphp.conf:

[handlers]
;Handler for php-scripts
;x-httpd-php="php:/usr/bin/php-cgi"
x-httpd-php="php:/home/admispconfig/ispconfig/tools/suphp/usr/bin/php-wrapper"

;Handler for CGI-scripts
x-suphp-cgi="execute:!self"

Then it should work.