debugging php

hello, i need to debug php. usually i do this by using my own-written debugger-class where i can turn off all output with a simple change of the "on" variable. well nevertheless now i need to trace the status and value of a variable during runtime. this is impossible with this class. so i tried to use the php debugger (php.ini: debugger.enabled = True). this leeds to some problems: - what is a good tcp-listener (i tried tcpdump, but this gives to much output) - the debugger doesn't work: the command debugger_on("localhost"); leads to the error-message shown below: Fatal error: Call to undefined function: debugger_on() in index.php on line 2 ... and the manual says, that the debugger is still under development. does anyone know, how to debug php-scripts? thanx for your help, mOrP