“service is deprecated and will be removed in a future release of Mac OS X”
do shell script "service --test-if-configured-on ftp"
No matter what service i try, this gives always “error “The command exited with a non-zero status.” number 1”
Maybe it was deprecated, and not updated after it stopped working. 
Try launchctl instead ( man launchctl ).
Service is a command to start and stop services located in inet.d and lookup the status. Since Tiger you have to use launchctl to start and stop services because initd (process zero) is now inside launchd.