Like many, I\'ve spent more hours debugging my IDE’s connection to XDebug than I have using XDebug to debug my programs. I’ve gotten it to work repeat
Please read this thread.
http://forums.netbeans.org/post-99369.html
in the end the workaround was to add net.ipv6.bindv6only = 0 to the file /etc/sysctl.d/bindv6only.conf and then reboot. Xdebug worked fine after that.