when you turn on developer mode you have to enter a password remember it.
after developer mode is on go back to the home screen.
click on the icon of the person with the cog in the middle
it will say development mode on expires in 10 days IP address 192.168.XXX.XXX (or whatever ip address you have setup)
open ddpb
click add and add the file you want
make sure it is "checked"
enter your ip address
enter your password
hit install.
if the icon does not appear in your list then the following happened.
1. IP address is wrong (DDPB will still say the transfer is done without an error)
2. Password is wrong (I believe it is case sensitive. DDPB will still say the transfer is done without an error)
3. bar file you are trying to add is not signed (did you try one from here
http://bit.ly/apk2bar this list has signed bar files)
if none of these are the problem then you could try a security wipe that seems to fix most problems.