The absolute path:

/home/strato/www/first_two_letters_of_your_domain/www.yourstratodomain.eu/htdocs/

Example:
/home/strato/www/yo/www.yourstratodomain.eu/htdocs/
-or-
/home/strato/www/st/www.strato-hosting.co.uk/htdocs

Please replace your "yourstratodomain.eu" with a domain from your internet package.

The path to Sendmail:

/usr/lib/sendmail

The path to Perl:

/usr/bin/perl

The path to Python:

/usr/bin/python

Note:
Please note that PHP and Perl are available in all STRATO hosting packages, however access to MySQL databases is only available from the PowerWeb package upwards.