juno-ds as a midi output device help.

i recently purchased a juno-ds , i wanted to play my midi backing tracks and play along the piano parts in my gigs.
 
the problem is when i connect my laptop to my junods , the midi sounds wierd.. some are piano sounds and others dont sound at all.  i dont have this problem before with my old sc-88..
 
can sonar/cakewalk help me with this?