lets assume you're connecting from Z to the PC, the latter is running linux
is sdpd running on the PC, and if you use "sdptool browse" on Z does it see the PC? If it won't do anything, try deleting the file /etc/bluetooth/link_key on both, and check the pin.
if sdptool indicates the Z can see the PC, have you tried running pand manually at both ends, connect on Z, listen on PC?