First a few questions:
Which version of the OSBDM are you using (hardware / software)?
Which version of CW are you using?
Which micro are you targeting?
My first guess would be that you are not communicating with the target device or it may not be in background debug mode.
Double check your connections from the JB16 to the level transcievers and to the 6-pin BDM header.
If you are using a BDM similar to our with the 74VC1T45 transcrivers, make sure you have the pull-up resistor and reset cap on the reset transciever input.
Check you crystal input on the target device. Make sure it is within spec of the OSBDM you built.
From the debugger, go to the "HCS08 Open Source BDM" menu, select "Setup" and check the "show protocol" box. Save the debugger configuration and when you re-connect you will see all the data being sent/received via the BDM. This may give you a better idea of what is going wrong.
If all else fails, buy one of ours :smileyhappy: